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Source: https://pcbassemblytech.com/feed/

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<title>16 Tips for High-Frequency PCB Design</title>
<link>https://pcbassemblytech.com/high-frequency-pcb-design/</link>
<dc:creator><![CDATA[PCBA Tech]]></dc:creator>
<pubDate>Wed, 17 Jan 2024 09:06:20 +0000</pubDate>
<category><![CDATA[Technology]]></category>
<guid isPermaLink="false">https://pcbassemblytech.com/?p=3809</guid>
<description><![CDATA[High-frequency PCB design is crucial for ensuring the proper functioning of electronic devices in various electromagnetic environments. It involves careful…]]></description>
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High-frequency PCB design is crucial for ensuring the proper functioning of electronic devices in various electromagnetic environments. It involves careful consideration of transmission lines, insulation materials, ground planes, and signal traces to minimize signal degradation and electromagnetic interference. In this blog, we will explore essential techniques and methods to achieve efficient high-frequency PCB design for electromagnetic compatibility (EMC).
45° Angle Traces for Reduced Return Loss
To mitigate return loss, using 45° angled traces for sharp turns in the PCB layout is essential. These angled traces help maintain signal integrity and reduce signal reflections, especially in high-frequency applications.
Controlled Dielectric Materials for Enhanced Performance
Choose high-performance PCBs with controlled dielectric constant values for each layer. This practice helps in effectively managing the electromagnetic fields between insulation materials and adjacent traces, reducing signal distortion and loss.
Precise PCB Etching Specifications
High-frequency PCBs require precise etching specifications to maintain signal accuracy. Consider specifying a line width total error of +/- 0.0007 inches, managing undercut and cross-sectional shape of traces, and specifying plating conditions for sidewalls. Properly managing trace geometries and coating surfaces is crucial to address skin effect issues related to microwave frequencies.
Minimize Lead Inductance and Opt for SMT Components
In high-frequency environments, it’s advisable to avoid using components with leads, as they introduce lead inductance. Instead, opt for surface mount technology (SMT) components, which offer better high-frequency performance and reduced parasitic effects.
Avoid Plated Through-Holes (PTH) on Sensitive Traces
Plated through-holes (PTH) on sensitive PCBs can introduce lead inductance and should be avoided. Instead, consider alternative methods such as blind vias or buried vias for connecting signal layers, which reduce electromagnetic interference.
Incorporate Abundant Ground Planes
Include multiple ground planes in the PCB design and connect them using via stitching to counter the impact of 3D electromagnetic fields on the circuit board. Adequate grounding helps in reducing noise and enhances signal integrity.
Choose Non-Electrolytic Nickel or Immersion Gold Plating
Avoid using Hot Air Solder Leveling (HASL) for plating, and instead, opt for non-electrolytic nickel or immersion gold plating. This surface finish provides a better skin effect for high-frequency currents and minimizes lead requirements, thereby reducing environmental pollution.
Employ Solder Dams for Solder Mask
To prevent solder paste flow, use solder dams (also known as solder mask dams). However, covering the entire PCB surface with solder mask can lead to variations in electromagnetic energy in microstrip designs. Carefully manage signal transitions between microstrip and coaxial cables to minimize signal loss and noise.
Electromagnetic Compatibility (EMC) Design
EMC design ensures electronic devices can function effectively and harmoniously in various electromagnetic environments. It involves suppressing external interference while also reducing the device’s electromagnetic emissions.
Optimal Trace Width Selection
To minimize the impact of transient currents and induced interference, choose trace widths that result in lower inductance. Short, precise traces are preferred as they contribute to reducing electromagnetic interference. For discrete component circuits, a trace width of approximately 1.5mm is suitable, while widths between 0.2mm and 1.0mm are commonly used for integrated circuits.
Strategic Routing
Equal-length routing can help reduce trace inductance but increases mutual inductance and distributed capacitance between traces. If possible, adopt a cross-hatch or grid-like routing pattern, where one side of the PCB contains horizontal traces and the other has vertical traces, interconnected using plated-through holes.
Minimizing Crosstalk
To mitigate crosstalk between PCB traces, avoid lengthy parallel routing of traces and ensure proper spacing between traces. Signal lines should not intersect with ground or power lines. Implementing ground traces between sensitive signal lines can effectively suppress crosstalk.
Suppressing Electromagnetic Radiation
In high-frequency PCB designs, attention should be paid to reducing electromagnetic radiation caused by signal traces. To achieve this:
Maintain trace continuity to prevent abrupt changes in trace width.
Place clock signal traces close to the ground plane return path and locate drivers adjacent to connectors.
Position bus drivers next to the buses they drive. For off-board signals, place drivers close to connectors.
Route data buses with a signal ground trace between every two signal lines. Consider placing the least critical address lines close to the ground return path, as they often carry high-frequency currents.
Arrange high-speed, medium-speed, and low-speed logic circuits according to best practices.
Controlling Reflection Interference
To suppress reflections at the termination of signal traces, strive to minimize trace lengths and use slower signal rates when possible. Termination matching can be applied when necessary by adding resistors of the same value at the end of transmission lines. Typically, termination matching is necessary for TTL circuits with higher speeds for trace lengths exceeding 10cm. The resistor value should be determined based on the output drive current and maximum sink current of the integrated circuits.
Implementing Differential Signal Pair Routing
Differential signal pairs that are routed closely together also experience mutual coupling, which can reduce EMI emissions. Since differential signals are often high-speed signals, high-speed design principles also apply to their routing. It is crucial to ensure that the characteristic impedance of the differential pairs is continuous along the entire length of the traces. In practical applications, efforts should be made to ensure that the differential pairs have identical impedance and length. Differential traces are typically routed as pairs and should maintain a constant distance between them. It is preferable to keep them as close together as possible.
Conclusion
Designing high-frequency PCBs requires careful consideration of various factors, including trace angles, dielectric materials, grounding techniques, and signal routing. Following the recommended techniques and strategies discussed in this blog will improve signal integrity, reduced electromagnetic interference, and enhanced electromagnetic compatibility. Achieving optimal high-frequency PCB design is essential to ensure the reliable and efficient performance of electronic devices in complex electromagnetic environments.When you finish designing a high-frequency PCB, you need a real manufacturer to help you realize the final work. If you are looking for some top PCB manufacturers, you can <a href="https://www.eashub.com/top-china-pcb-manufacturers/" data-type="link" data-id="https://www.eashub.com/top-china-pcb-manufacturers/" target="_blank" rel="noopener">visit here</a>.
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<item>
<title>What are Common Issues during PCB Manufacturing & PCBA assembly？</title>
<link>https://pcbassemblytech.com/issues-during-pcb-manufacturing-pcba-assembly/</link>
<dc:creator><![CDATA[PCBA Tech]]></dc:creator>
<pubDate>Tue, 09 Jan 2024 07:47:38 +0000</pubDate>
<category><![CDATA[PCB Manufacturing]]></category>
<category><![CDATA[PCB Assembly]]></category>
<guid isPermaLink="false">https://pcbassemblytech.com/?p=3818</guid>
<description><![CDATA[Q1: What is the cause of poor wetting during PCBA assembly? A: Poor wetting during soldering occurs due to various…]]></description>
<content:encoded><![CDATA[
Q1: What is the cause of poor wetting during PCBA assembly?
A: Poor wetting during soldering occurs due to various reasons:
Presence of gases on the substrate surface during wave soldering.
Residual metals in solder exceeding 0.005%, reducing flux activity.
Surface contamination on soldering areas or component surfaces, such as silver sulfide or oxide on tin surfaces, leading to poor wetting.
Solution:
Adhere strictly to the corresponding soldering processes.
Ensure thorough cleaning of PCB and component surfaces.
Opt for appropriate solder and set reasonable soldering temperatures and durations.
Q2: What causes the phenomenon of “tombstoning” in components during assembly?
A: Tombstoning, where one end of a component fails to contact the solder pad and stands upright, arises from various factors:
Solder paste wetting properties.
Inherent component shapes prone to tombstoning.
Rapid or uneven heating during reflow soldering.
Incorrect solder paste selection, lack of preheating, or wrong soldering zone dimensions.
Solution:
Set appropriate solder paste printing thickness.
Establish controlled temperature ramp-ups during reflow.
Store and handle electronic components according to specifications.
Minimize surface tension on component ends during solder melt.
Preheat PCBs uniformly to ensure even heating during soldering.
Q: What methods can prevent the formation of soldering voids during PCBA assembly?
Q1: How can prolonged exposure to air be prevented for PCBs and components to avoid moisture loss?
A: Implement baking as a preventive measure. PCBs and components exposed to air for extended periods can undergo baking, effectively preventing moisture loss.
Q2: What measures should be taken regarding solder paste to prevent the occurrence of soldering voids and solder balls?
A: Several steps can be taken regarding solder paste:
Opt for high-quality solder paste to minimize issues.
Strictly adhere to the solder paste stirring process, minimize exposure time to air, and promptly reflow after printing.
Q3: How crucial is workshop humidity control in preventing soldering voids?
A: Workshop humidity control is paramount. Maintain planned monitoring of workshop humidity levels between 40-60% to prevent moisture-related issues.
Q4: How can optimal furnace temperature profiles help prevent soldering voids?
A: Setting reasonable furnace temperature profiles and performing daily temperature tests twice help optimize profiles. Avoid excessively rapid heating rates.
Q5: What considerations should be made regarding flux application to avoid soldering voids during wave soldering?
A: Ensure moderate flux application during wave soldering to prevent excessive flux and ensure proper application.
Q6: How can the optimization of reflow furnace temperature profiles contribute to minimizing soldering voids?
A: Optimize reflow furnace temperature profiles by ensuring preheat zone temperatures meet requirements without being too low, allowing sufficient flux evaporation, and avoiding excessively rapid heating rates.
Q: What are common issues encountered during PCBA board soldering, and how can they be resolved effectively?
A:
Q1: How does unstable soldering temperature affect PCBA board quality, and what solutions exist?
A: Unstable soldering temperatures directly impact solder joint quality during PCBA board assembly. Maintaining proper temperature is crucial to prevent damage to components. Solutions involve selecting appropriate soldering equipment, conducting temperature calibration, and adjusting soldering temperature and duration based on component specifications to ensure stable soldering quality.
Q2: What causes uneven soldering spacing, and how can this issue be addressed during PCBA board assembly?
A: Uneven soldering spacing often results from irregular component arrangement or inadequate board design. To resolve this issue, plan soldering layouts in advance, arrange component positions logically, and ensure soldering spacing adheres to specified requirements. Additionally, auxiliary positioning tools like soldering templates or guide pins aid in adjusting soldering positions, enhancing overall soldering quality.
Q3: How does one ensure the robustness of solder joints to enhance PCBA board reliability?
A: The strength of solder joints directly impacts PCBA board reliability. Weak joints can lead to breakage or detachment, affecting the board’s functionality. To address weak joints, choose appropriate soldering materials and methods ensuring good contact between solder and pads. Control soldering time and pressure appropriately, utilize support fixtures like soldering jigs or adhesive to enhance joint stability.
Q4: How can one safeguard temperature-sensitive components during PCBA board assembly?
A: Components in PCBA boards, especially precision ones, are highly sensitive to temperature. Incorrect temperatures or methods during soldering can damage or impair their performance. To prevent this, employ protective measures like thermal tape or heat sinks before soldering. Additionally, maintain suitable soldering temperatures and durations to avoid overheating components.
Q5: What precautions are necessary to prevent electrostatic discharge (ESD) issues during PCBA board assembly?
A: ESD can severely damage PCBA boards and their components. Implement ESD protection measures before soldering by using anti-static clothing, gloves, and footwear. Employ suitable ESD protection devices to prevent static discharge from causing harm to the boards.
Q: What are the potential issues during PCBA manufacturing, and how can they be resolved?
A:
Q1: What are the signs and causes of various soldering problems encountered in PCBA assembly?
A: Signs like cold solder joints or bursting holes can stem from insufficient copper plating or stress on the copper during soldering. Addressing this involves analyzing plated holes before and after soldering to identify stressed areas, performing incoming material inspections, and possibly changing materials to reduce stress, as suggested by the laminate board manufacturer.
Q2: How does detachment of pads and wires occur during PCBA assembly, and what measures can prevent it?
A: Detachment during soldering may result from plating solution effects, solvent erosion, or stress on copper during electroplating. It can also be due to poor soldering techniques or high temperatures. To prevent this, provide a detailed solvent and solution list to the laminate board manufacturer, analyze the electroplating process, and ensure compliance with recommended machining methods.
Q3: What leads to excessive size changes post-assembly, and how can this issue be addressed?
A: Post-assembly size changes can result from directional construction texture ignorance or localized stress within the laminate board. To mitigate this, consistently align material according to construction texture direction and, if size changes exceed tolerance, consider changing the material or seeking advice from the laminate board manufacturer on stress release methods pre-assembly.
Hope our above answers can answer your questions, if you are looking for some top PCB manufacturers you can refer here:<a href="https://www.eashub.com/top-china-pcb-manufacturers/" target="_blank" rel="noopener">https://www.eashub.com/top-china-pcb-manufacturers/</a>
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</item>
<item>
<title>5 Key Considerations in RF Circuit Board Design</title>
<link>https://pcbassemblytech.com/key-considerations-in-rf-circuit-board-design/</link>
<dc:creator><![CDATA[PCBA Tech]]></dc:creator>
<pubDate>Fri, 22 Dec 2023 03:20:00 +0000</pubDate>
<category><![CDATA[Technology]]></category>
<guid isPermaLink="false">https://pcbassemblytech.com/?p=3800</guid>
<description><![CDATA[RF (Radio Frequency) circuit board design involves several critical factors that must be considered to ensure optimal performance and minimal…]]></description>
<content:encoded><![CDATA[
RF (Radio Frequency) circuit board design involves several critical factors that must be considered to ensure optimal performance and minimal electromagnetic interference. While there are guidelines to follow in RF circuit board design, practical techniques are required when facing constraints and compromises. In this blog, we will explore various aspects related to RF circuit board partitioning and delve into important considerations for successful RF circuit board design.
Types of microvias:
Microvias are crucial in connecting different circuit components on a PCB while maintaining minimal electromagnetic interference. They are categorized into three types: blind vias, buried vias, and through vias. Blind vias connect the top and bottom layers of the PCB to the inner layers, while buried vias stay entirely within the inner layers. Through vias span the entire PCB, enabling internal interconnections or serving as component mounting holes.
Adopting Partitioning Techniques:
In RF circuit board design, isolating high-power RF amplifiers (HPAs) from low-noise amplifiers (LNAs) is essential. This isolation ensures that high-power RF transmission circuits are kept away from low-noise receiving circuits. While this separation is relatively straightforward when the PCB has ample space, it becomes more challenging when dealing with limited space and numerous components. In such cases, placing the circuits on opposite sides of the PCB or operating them alternately instead of simultaneously can be beneficial. High-power circuits may also include RF buffers and voltage-controlled oscillators (VCOs).
The partitioning can be physical, focusing on component layout, orientation, and shielding, or electrical, dealing with power distribution, RF routing, sensitive circuitry, and grounding.
Physical Partitioning:
Proper component layout is crucial for achieving excellent RF design. The most effective technique involves placing components along the RF path and adjusting their orientation to minimize the length of the RF path. RF inputs should be far from RF outputs and as distant as possible from high-power and low-noise circuits.
An effective PCB stack-up technique is to place the primary ground on the second layer beneath the surface layer and route RF traces on the surface layer whenever possible. Minimizing the size of vias along the RF path reduces path inductance, minimizes parasitic effects, and reduces the chances of RF energy leakage to other regions of the PCB stack-up.
Careful attention must be given to minimizing interference between RF/IF signals in devices such as duplexers, mixers, and intermediate frequency amplifiers, where multiple RF/IF signals interact. RF and IF traces should ideally cross each other at right angles, with sufficient ground areas between them. Proper RF routing is critical for overall PCB performance, making component layout time-consuming in mobile phone PCB design.
In mobile phone PCBs, low-noise amplifiers are often placed on one side of the PCB, while high-power amplifiers are positioned on the other side, connected through duplexers to the RF antenna on one end and the baseband processor on the other. Special techniques, like using blind vias on both sides of the PCB, can help minimize the negative effects of vias on RF energy transmission.
Metal Shielding:
In cases where it is challenging to maintain sufficient isolation between multiple circuit blocks, metal shielding can be employed to contain RF energy within specific areas. However, metal shielding also has drawbacks, such as increased manufacturing and assembly costs.
Irregularly shaped metal shielding is challenging to produce with high precision, while rectangular or square metal shields may restrict component layout. Metal shields can impede component replacement and fault troubleshooting, and their attachment to the ground plane consumes valuable PCB space.
To ensure the integrity of metal shielding, digital signal lines entering the shield should follow inner layers, with the next layer being a ground plane. RF signal lines can exit the metal shield through small gaps at the bottom, with ample ground area surrounding the gaps. Ground connections on different signal layers can be achieved through multiple vias. Despite these drawbacks, metal shielding remains effective, often being the only viable solution to isolate critical circuits.
Power Decoupling Circuits:
Effective power decoupling is essential to minimize noise in RF chips, especially those integrating linear circuits. Typically, each chip requires up to four capacitors and one isolation inductor to filter all power supply noise.
The minimum capacitor value is determined by the capacitor’s resonance frequency and lead inductance (C4). C3 and C2 usually have relatively larger values due to their own lead inductance, resulting in less effective RF decoupling. However, they are suitable for filtering lower-frequency noise signals. RF decoupling is achieved with inductor L1, preventing RF signals from coupling into the power supply lines. Due to the potential for all traces to act as antennas, isolating RF signals from critical lines and components is crucial.
The physical positioning of these decoupling components is also critical. The layout principles for these components include placing C4 as close to the IC pin as possible and grounding it. C3 should be closest to C4, and C2 should be closest to C3. The connection between the IC pin and C4 should have the shortest trace possible. The ground terminal of these components, especially C4, should be connected to the chip’s ground pin via the first ground layer beneath the PCB surface. The vias connecting the components to the ground layer should be placed as close to the component pad as possible, and using blind vias on the pad can minimize inductance. Inductor L1 should be placed near C1.
In some cases, an integrated circuit or amplifier may have an open collector output, necessitating a pull-up inductor to provide a high-impedance RF load and a low-impedance DC power source. The same principles apply to decoupling the power end of this inductor. Some chips require multiple power supplies, necessitating two to three sets of capacitors and inductors for proper decoupling. If there is insufficient space around the chip, the effectiveness of decoupling may be compromised. Additionally, inductors should not be placed parallel to each other, as this would create a transformer with mutual inductance causing interference. Their spacing should be at least equal to the height of either inductor, or they should be arranged at right angles to minimize mutual inductance.
Conclusion:
Designing RF circuit boards involves balancing multiple factors to achieve optimal performance, minimize interference, and meet space constraints. Microvias, partitioning techniques, metal shielding, and proper power decoupling are critical aspects of successful RF circuit board design. By carefully considering these factors and implementing practical strategies, engineers can develop high-performance RF circuit boards that meet the demands of modern communication systems and devices.
Hope our above answers can answer your questions, if you are looking for some top PCB manufacturers you can <a href="https://www.eashub.com/top-china-pcb-manufacturers/" data-type="link" data-id="https://www.eashub.com/top-china-pcb-manufacturers/" target="_blank" rel="noopener">visit here.</a>
]]></content:encoded>
</item>
<item>
<title>LED Display Driver IC Industry Current Status And Development</title>
<link>https://pcbassemblytech.com/led-display-driver-ic/</link>
<dc:creator><![CDATA[PCBA Tech]]></dc:creator>
<pubDate>Thu, 16 Nov 2023 07:10:20 +0000</pubDate>
<category><![CDATA[Technology]]></category>
<guid isPermaLink="false">https://pcbassemblytech.com/?p=3814</guid>
<description><![CDATA[As a high-tech product, LED display screens have played an indispensable role in conveying essential information and providing unparalleled visual…]]></description>
<content:encoded><![CDATA[
As a high-tech product, LED display screens have played an indispensable role in conveying essential information and providing unparalleled visual experiences in people’s daily lives after more than two decades of market development. Controlled by computers, these intelligent full-color LED display screens integrate light and electricity, widely applied in various fields. They utilize LED pixels arranged in an array to form screens that showcase different images based on varied LED driving methods. The quality of LED display screens heavily relies on the specialized driver ICs.
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<h2 class="wp-block-heading">Basic Concept of Driver ICs</h2>
a. Introduction to Display Driver ICs
LED display screen specialized driver chips are specifically designed for driving LED display screens based on LED luminous characteristics. These driver ICs significantly impact the grayscale and refresh rate of LED screens. The maturity of LED display screen driver IC technology has propelled a qualitative leap in display quality. With features like high output current and constant current, these driver ICs enable LED screens to be used in high-current, high-resolution scenarios, driving the diversity of displayed content and application fields.
LED driver chips can be divided into general-purpose and specialized types. General-purpose chips, like the 74HC595, are not specifically designed for LEDs but serve logic functions for LED screens, typically used in lower-end products like indoor single or dual-color screens. Specialized chips are tailored for LED screens, providing constant current sources crucial for stable LED driving, eliminating flickering, and ensuring high-quality visuals. Top <a href="https://iamledwall.com/" data-type="link" data-id="https://iamledwall.com/" target="_blank" rel="noopener">Used LED display provider like IAMLEDWALL</a> used some specialized chips incorporate additional functions tailored to different industry requirements, such as LED error detection, current gain control, and current correction.
Performance Metrics of Driver ICs
In LED display screens, refresh rate, grayscale levels, and image representation are vital metrics, demanding high consistency in channel currents, fast communication interface rates, and constant current response from LED driver ICs. Traditionally, there’s been a trade-off between refresh rate, grayscale, and utilization – ensuring one or two metrics are excellent often sacrifices the others. However, advancements in technology from driver IC manufacturers have mitigated these issues.
In addition to these, in applications of LED full-color display screens, maintaining low brightness with high grayscale becomes a critical standard, testing the performance of driver ICs.
<h2 class="wp-block-heading">Role, Working Principle, and Driving Modes of LED Driver ICs</h2>
The primary role of <a href="https://iamledwall.com/led-display-scan-modes-and-driving-principles/" data-type="link" data-id="https://iamledwall.com/led-display-scan-modes-and-driving-principles/" target="_blank" rel="noopener">LED driver ICs</a> involves receiving display data following specified protocols (from receiving cards or video processors) and internally generating PWM and current variations, outputting PWM currents related to brightness and grayscale to illuminate LEDs. These driver ICs, together with logic ICs and MOS switches, collectively influence the display functions and the resultant visual effects of LED screens.
The driver chip contains a constant current generation circuit, allowing the setting of output constant current values via external resistor configuration. Through the chip’s enable terminal, control over the switch time of output channels is achieved, with a switching frequency of up to one megahertz (1MHz). The rapid response of current output supports applications with high-color gradation changes and high screen refresh rates. Built-in open-circuit detection, overheat shutdown, and overcurrent protection greatly enhance the reliability of application systems.
Driver ICs are mainly categorized into constant current and voltage stabilizing driving modes.
Constant current driving maintains a consistent output current, while the output DC voltage varies within a certain range depending on the load resistance; however, it’s essential to avoid complete load open circuits, and these circuits can be relatively expensive. The maximum permissible current and voltage values used restrict the number of LEDs that can be employed.
Voltage stabilizing driving maintains a fixed output voltage, while the output current fluctuates with changes in the load; these circuits can withstand load open circuits but strictly prohibit complete load short circuits. To drive LEDs using voltage stabilizing circuits, suitable resistors need to be added to ensure uniform brightness across LED strings, which can be influenced by voltage fluctuations from rectification.
<h2 class="wp-block-heading">The development and overview of LED display driver ICs in China </h2>
1. Evolution of LED Display Driver ICs
In the 1990s, LED display screens primarily used single or dual-color displays with constant voltage driver ICs. In 1997, China introduced the specialized LED display driver control chip 9701, which leaped from 16-level grayscale to 8192-level grayscale, enabling real-time video rendering. Subsequently, due to the light-emitting characteristics of LEDs, constant current driving became the choice for full-color LED displays. Higher integration of 16-channel drivers replaced 8-channel ones. Towards the late ’90s, companies like Toshiba (Japan), Allegro, and TI (USA) introduced 16-channel LED constant current driver chips. In the early 21st century, Taiwanese companies also started mass-producing and using these driver chips. Additionally, some IC manufacturers introduced highly integrated 48-channel LED constant current driver chips to solve PCB wiring issues for small-pitch LED displays.
2. Current Status of Driver IC Market
Since Q4 2020, due to robust market demand and increased raw material costs, display driver IC manufacturers have raised product prices by approximately 10% to 20%. Amid rising costs, they initiated another round of price hikes from April, reaching up to 15% to 20%. The shortage of display driver ICs began around Q3 2020, with supply initially meeting only 50% of market demand, causing distress for small and medium enterprises. This scarcity eased towards the end of 2021.
Under the “chip shortage” wave starting in 2021, some display IC prices surged by 30%, even reaching a situation of demand without a price tag. This shortage significantly affected the LED display industry, given China’s relatively high dependence on high-end chip imports. The global shipment of driver chips is expected to reach 122.14 billion units in 2023, with an estimated 45.651 billion units in the Chinese market.
In 2021, the total sales of domestic display driver ICs reached around 5 billion RMB, primarily benefiting from a surge in demand in the second quarter of the previous year, causing price spikes. This surge, initially perceived as monopolistic behavior by industry professionals, led to related disputes.
3. Development of Mini/Micro LED Technology and its Challenge to Traditional Driver ICs
The specialized LED display driver ICs sell approximately 1 billion units per month in China. With the rapid development of Mini/Micro LED technology and accelerated application market demand, the requirement is expected to exceed 2 billion units per month by 2024.
Technological advancements drive high-quality innovation in the display industry. The LED display driver IC, functioning as the central nervous system similar to the human brain, governs the visual effects of the entire display. In applications like small-pitch LED displays, maintaining comfortable viewing for prolonged periods requires stringent standards such as low brightness and high grayscale in driver IC performance.
4. Future Technological Development Directions for Driver ICs
Existing product technologies will continue optimizing to resolve issues like trailing shadows, “jitter,” grayscale, low brightness with high grayscale, enhancing refresh rates, picture quality, interference resistance, reducing power consumption, and smart energy efficiency. Due to current IC sizes not meeting demands for Mini/Micro LED ultra-fine pitch and ultra-dense chip products, related IC products will evolve towards higher integration.
Efficiency remains a perpetual pursuit in LED displays as green energy sources, driving the evaluation of driver IC performance. Efforts focus on effectively reducing constant current inflection voltage, decreasing operational voltage, and current while optimizing IC algorithms and designs. Some manufacturers have introduced constant current driver ICs with a low transition voltage of 0.2V, improving LED utilization by over 15% compared to conventional products, leading to a 16% reduction in power consumption.
As pixel pitch rapidly decreases in LED displays, the number of components per unit area significantly increases. For instance, a P1.9 small-pitch LED requires 180 constant current driver ICs, 45 row drivers, and 2 138 drivers for a 15-scan 160*90 module. This density challenges PCB wiring space and circuit design while impacting module reliability. The demand for fewer driver ICs and more PCB wiring area compels driver ICs towards highly integrated technological pathways.
<h2 class="wp-block-heading">Industry Outlook for Display Driver ICs</h2>
Impact of Pandemic on IC Production Capacity: The pandemic affected new expansions and production lines of IC companies in regions like Shanghai, Suzhou, and Wuxi, slowing down new capacity releases. However, increased demand for LED displays in Q2 2021, followed by a slowdown due to the pandemic in early 2022, added to inventory pressures. The industry, including driver ICs, might experience relief from supply-demand tension.
New Requirements in the Era of Ultra-Fine Pitch Displays: As Mini/Micro LED applications accelerate in the consumer electronics industry, more IC companies might enter the LED display domain, potentially alleviating supply-demand pressures.
In light of these trends, the LED display industry increasingly demands driver IC performance optimization. Meeting these demands entails focusing on multiple requirements like low power consumption, low grayscale with high refresh rates, grayscale correction, high integration, high frame rates, PWM+AM, etc.
Design-wise, meeting low-power circuit design necessitates optimizing internal circuit power consumption, achieving over 48 channels for high integration, and adopting 128-scan high scan designs. Control modules should operate at low power, reducing power consumption from 12.5 (W/㎡) to 2 (W/㎡). Technological advancements from 180nm to 40nm are essential to meet these requirements.
With applications in various sectors escalating, meeting new market demands through technological advancements remains a key task for the industry to prepare for future market needs.
<h2 class="wp-block-heading">Conclusion</h2>
LED display driver ICs play a crucial role in driving the development of LED displays. The constantly evolving landscape of LED display applications poses challenges for driver ICs, necessitating substantial breakthroughs in technology to aid the industry’s growth. Future advancements will likely reveal the true potential of LED displays, inspiring further innovation in driver ICs.
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<title>Best RF PCB Layout and Routing Practices for Mobile Phones</title>
<link>https://pcbassemblytech.com/best-rf-pcb-layout-and-routing-practices-for-mobile-phones/</link>
<dc:creator><![CDATA[PCBA Tech]]></dc:creator>
<pubDate>Tue, 25 Jul 2023 03:17:08 +0000</pubDate>
<category><![CDATA[Technology]]></category>
<guid isPermaLink="false">https://pcbassemblytech.com/?p=3811</guid>
<description><![CDATA[RF (Radio Frequency) PCB layout and routing are critical aspects of mobile phone design. Careful consideration and proper implementation of…]]></description>
<content:encoded><![CDATA[
RF (Radio Frequency) PCB layout and routing are critical aspects of mobile phone design. Careful consideration and proper implementation of these techniques are essential to ensure optimal performance and reduce interference. In this post, we will discuss several key factors to prioritize when designing mobile phone PCBs.
Power and Ground Plane Handling:
Even with a well-designed PCB layout, inadequate handling of power and ground planes can lead to interference and decreased product performance. Therefore, minimizing noise interference between power and ground lines is crucial. Here are some strategies to achieve this:
1) Add decoupling capacitors between power and ground lines.
2) Widen power and ground traces, with ground traces generally wider than power traces. The relationship between trace widths can be Ground trace > Power trace > Signal trace. Typical signal trace width is around 0.2 – 0.3mm, and the minimum trace width can be as small as 0.05 – 0.07mm, while power traces are between 1.2 – 2.5mm wide. For PCBs with digital circuits, a wide ground trace can form a loop to create a ground plane (this may not be suitable for analog circuits).
3) Utilize large copper areas for the ground plane. Unused areas on the PCB can also be connected to the ground plane. Alternatively, consider using multilayer boards where power and ground planes occupy separate layers.
Shared Ground Handling for Digital and Analog Circuits:
Modern PCBs often consist of a mix of digital and analog circuits. Therefore, designers must address the issue of mutual interference, especially concerning noise on the ground plane. High-frequency signals from digital circuits and the sensitivity of analog circuits demand careful consideration. To mitigate this, follow these guidelines:
1) Keep high-frequency signal traces from sensitive analog components as far away as possible.
2) Internally separate digital and analog ground planes. They should not be connected within the PCB except at specific interface points with the external world (e.g., connectors). There should be only one connection point between the digital and analog ground planes. However, there are cases where separate ground planes are necessary based on system design.
Signal Routing on Power (or Ground) Layers:
When dealing with multilayer PCBs, it is common to have some unused traces after routing on signal layers. To avoid waste and minimize production costs, consider routing on power (or ground) layers. Start by utilizing the power layer and then the ground layer, as maintaining the integrity of the ground plane is essential.
Handling Component Connections in Large Copper Areas:
In large ground or power areas, components often have their legs connected to them. It is essential to consider these connections carefully to balance electrical performance and assembly requirements. Connecting component legs directly to the copper area is good for electrical performance but may have drawbacks during assembly, such as:
1) The need for high-power heating during soldering.
2) Increased likelihood of solder joint defects.
To address these issues, consider using thermal relief pads or heat shields (also known as thermal pads). These features help dissipate heat more evenly during soldering and reduce the risk of solder joint defects. Similar considerations apply to legs connected to power or ground layers in multilayer PCBs.
Role of Network Systems in Routing:
Many CAD systems use network systems to determine routing paths. A dense network may increase routing possibilities but can result in larger data files and potentially slow down the device’s operation. Conversely, a sparse network can limit routing options and impact signal integrity. Therefore, a balanced network system that supports efficient routing is crucial. Standard component leg spacing is 0.1 inches (2.54mm), so the network system’s base is often set at 0.1 inches or smaller multiples, such as 0.05 inches, 0.025 inches, or 0.02 inches.
Conclusion:
Proper RF PCB layout and routing are vital for the optimal performance of mobile phones. By focusing on power and ground plane handling, shared ground management for digital and analog circuits, signal routing on power (or ground) layers, component connections in large copper areas, and the role of network systems in routing, designers can achieve high-quality, low-interference PCBs, leading to superior mobile phone performance.
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<title>4 Key Considerations for Smart Bracelets PCB Design</title>
<link>https://pcbassemblytech.com/considerations-for-smart-bracelets-pcb-design/</link>
<dc:creator><![CDATA[PCBA Tech]]></dc:creator>
<pubDate>Tue, 25 Jul 2023 03:00:53 +0000</pubDate>
<category><![CDATA[Technology]]></category>
<guid isPermaLink="false">https://pcbassemblytech.com/?p=3806</guid>
<description><![CDATA[Smart bracelets have gained significant popularity in recent years, capturing the attention of consumers and influencing the electronic product market.…]]></description>
<content:encoded><![CDATA[
Smart bracelets have gained significant popularity in recent years, capturing the attention of consumers and influencing the electronic product market. These devices typically consist of various components, including RF circuitry, clock circuitry, memory circuitry, sensor circuitry, and a main control MCU unit. The PCB layout for smart bracelets is usually compact, often utilizing single or double-sided surface-mount technology, with 4 or 6-layer boards being common. In this post, we will explore some essential considerations for PCB design in smart bracelets to ensure optimal performance and functionality.
Partitioned Layout and Wire Routing Protection:
A well-organized partitioned layout is crucial in smart bracelet PCB design. As smart bracelets are essentially collections of digital circuit elements, designing circuit modules with appropriate resistor and capacitor distributions simplifies the overall design and facilitates easy troubleshooting. Additionally, when routing clock and crystal oscillator circuits, creating the shortest possible paths to their target devices is essential. Care should be taken to avoid interference from data lines, ensuring system stability.
Critical signal traces, such as those related to clock generation and crystal circuits, should be protected. This protection may involve using copper pours or ground shielding to minimize interference. Special attention must be given to the crystal oscillator section, where copper pours may need to be removed to optimize performance.
Handling RF Circuitry:
Smart bracelets often rely on wireless communication, typically utilizing Bluetooth for data transfer and synchronization with smartphones. The RF section is a crucial design part and requires careful attention. For devices solely focused on data transmission without audio capabilities, low-power Bluetooth is often the preferred choice. During the design phase, factors like the shape and layout of the Bluetooth antenna and the choice of materials for the bracelet’s casing can significantly impact overall performance. Collaboration with an experienced RF antenna engineer can be invaluable in achieving optimal results.
ESD Protection:
Electrostatic discharge (ESD) protection is vital for smart bracelets to meet the relevant product standards and regulations in different countries and regions. Incorporating ESD protection into the design and performing thorough ESD testing post-design ensures that the product can withstand electronic testing in various markets.
Provision for System Upgrades:
Facilitating convenient software upgrades is essential for smart bracelets. As these devices continually undergo development and improvement, offering the ability to upgrade software provides users and enthusiasts with a sense of satisfaction. Two common methods for software upgrades are via USB interface or wireless transmission. The decision on which method to adopt should be made during the early planning stages, considering both hardware and software considerations.
Conclusion:
Smart bracelets represent a popular and dynamic product category in the electronics market. Efficient PCB design is crucial to ensure the proper functioning and performance of these devices. 
By considering the points, designers can create smart bracelets that deliver seamless connectivity, exceptional functionality, and a satisfying user experience. As this technology evolves, embracing these design considerations will remain essential to stay competitive in the smart bracelet market.
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<title>Electromagnetic Compatibility (EMC) Design for Mobile PCBs</title>
<link>https://pcbassemblytech.com/emc-design-for-mobile-pcbs/</link>
<dc:creator><![CDATA[PCBA Tech]]></dc:creator>
<pubDate>Sat, 22 Jul 2023 03:29:29 +0000</pubDate>
<category><![CDATA[PCB Manufacturing]]></category>
<category><![CDATA[Technology]]></category>
<guid isPermaLink="false">https://pcbassemblytech.com/?p=3804</guid>
<description><![CDATA[Electromagnetic Compatibility (EMC) is a crucial aspect of electronic device design, ensuring that devices can function effectively in various electromagnetic…]]></description>
<content:encoded><![CDATA[
Electromagnetic Compatibility (EMC) is a crucial aspect of electronic device design, ensuring that devices can function effectively in various electromagnetic environments. The primary goal of EMC design is to suppress external interference while minimizing the device’s electromagnetic emissions, reducing its impact on other electronic devices. In this blog post, we will explore essential EMC design considerations for mobile Printed Circuit Boards (PCBs), highlighting strategies to mitigate electromagnetic interference and maintain reliable device performance.
Choosing Optimal Trace Widths:
Transient currents generate disruptive interference primarily due to the inductive components of PCB traces. To minimize this effect, reducing the trace’s inductance is essential. The inductance of a trace is directly proportional to its length and inversely proportional to its width. Therefore, shorter and wider traces are preferable for interference suppression. Signal lines like clocks and bus drivers often carry significant transient currents, necessitating shorter trace lengths. For discrete component circuits, trace widths of around 1.5mm are sufficient, while widths between 0.2mm to 1.0mm are recommended for integrated circuits.
Adopting Proper Routing Strategies:
Equal-length routing reduces trace inductance but increases mutual inductance and distributed capacitance between traces. If the layout allows, a better approach is to use a cross-hatch or grid-like routing pattern. One side of the PCB can have horizontal traces, while the other side has vertical traces, interconnected at crossover points using plated-through holes.
Avoiding Crosstalk and Interference:
To suppress crosstalk between PCB traces, it’s crucial to avoid long, parallel routing of traces whenever possible. Designers should aim to increase the spacing between traces and minimize intersections between signal, ground, and power lines. Placing a ground trace between sensitive signal lines can effectively reduce crosstalk.
Reducing Electromagnetic Emissions:
To minimize electromagnetic radiation caused by high-frequency signals traveling through PCB traces, designers should consider the following:
(a) Avoid abrupt changes in trace width or sharp trace corners. Right-angle bends should be avoided, and traces should maintain a smooth path.
(b) Clock signal traces are particularly prone to electromagnetic radiation. They should be routed close to the ground return path, and drivers should be positioned adjacent to connectors.
(c) Bus drivers should be placed close to the bus they drive, and for off-board traces, drivers should be positioned near connectors.
(d) Data bus routing should involve placing a signal ground trace between every two signal lines. Ideally, the least critical address lines should be adjacent to the ground return path, as they often carry high-frequency currents.
(e) Following a suitable layout pattern is essential When arranging high-speed, medium-speed, and low-speed logic circuits.
Suppression of Reflection Interference:
To minimize reflection interference occurring at the end of PCB traces, the trace lengths should be shortened wherever possible, and slower circuits should be used, if feasible. Terminal matching can be applied if needed, involving the addition of a matching resistor to the ground and the power source at the end of transmission lines. Typically, terminal matching should be considered for trace lengths exceeding 10cm for fast TTL circuits. The value of the matching resistor should be determined based on the integrated circuit’s output drive current and the maximum sinking current.
Employing Differential Pair Routing:
Differential signals routed close to each other can mutually couple, reducing EMI emissions. Typically, differential signals are high-speed, making high-speed design rules applicable to their routing. Ensuring consistent characteristic impedance along the entire length of the signal lines is critical for differential pair routing. The PCB traces in a differential pair should be identical, with the same impedance and routing length. Maintaining consistent spacing between differential traces throughout their length is essential, and designers should aim to keep them as close together as possible.
Conclusion:
Effective electromagnetic compatibility (EMC) design is vital for mobile PCBs to ensure optimal performance and minimize interference in various electromagnetic environments. Designers can create mobile devices that operate reliably and efficiently by carefully selecting trace widths, employing proper routing strategies, mitigating crosstalk, reducing electromagnetic emissions, and implementing differential pair routing. These practices enhance the device’s functionality and contribute to the overall reliability and performance of electronic systems in today’s interconnected world.
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<title>Best Tips for PCB Design in LED Switching Power Supplies</title>
<link>https://pcbassemblytech.com/pcb-design-in-led-switching-power-supplies/</link>
<dc:creator><![CDATA[PCBA Tech]]></dc:creator>
<pubDate>Sat, 22 Jul 2023 03:24:11 +0000</pubDate>
<category><![CDATA[PCB Manufacturing]]></category>
<category><![CDATA[Technology]]></category>
<guid isPermaLink="false">https://pcbassemblytech.com/?p=3802</guid>
<description><![CDATA[The rapid technological advancements in LED power supplies have led to significant improvements in recent years, resulting in faster product…]]></description>
<content:encoded><![CDATA[
The rapid technological advancements in LED power supplies have led to significant improvements in recent years, resulting in faster product upgrades and replacements. Among the crucial stages of LED power supply development, PCB design plays a vital role. A well-executed PCB design ensures minimal electromagnetic interference and enhances the stability and safety of the entire LED switching power system. In this blog, we will explore the correct methods for PCB circuit design in LED switching power supplies, considering the placement of components, the layout of current loops, and the significance of filtering capacitors.
The Importance of PCB Design in LED Switching Power Supplies
Research and market practices have demonstrated that even if the circuit schematic is well-designed during the initial development phase, PCB design issues can adversely impact the reliability of electronic devices. Inadequate considerations for power and ground lines can lead to interference and result in degraded product performance. Therefore, adopting the right approach in designing PCBs is crucial to achieving optimal results in LED switching power supplies.
Critical Current Loops in LED Switching Power Supplies
A typical PCB for a switching power supply incorporates four current loops:
<ul>
<li>Input signal source current loop</li>
<li>Power switch AC current loop</li>
<li>Output rectifier AC current loop</li>
<li>Output load current loop</li>
</ul>
The input loop charges the input capacitors with nearly DC current, where the filtering capacitors act as wideband energy storage elements. Similarly, the output filtering capacitors store high-frequency energy from the output rectifier while eliminating DC energy from the output load loop. Proper wiring of the input and output filtering capacitors is essential, and the input and output current loops must connect only to the terminals of the filtering capacitors.
Setting up and connecting the input and output current loops significantly influence the level of electromagnetic interference. AC energy can radiate into the environment if the connections between the input/output loops and the power switch or rectifier are not directly linked to the capacitor terminals. The power switch AC loop and rectifier AC loop carry high-amplitude trapezoidal currents with significant harmonic components at frequencies much higher than the switching frequency. Their peak amplitudes can reach up to five times the amplitude of the continuous input/output DC currents, with a typical transition time of about 50ns. Consequently, these two loops are most prone to generating electromagnetic interference and should be laid out before other printed lines in the power supply.
Arranging Components in Input and Output Loops
Three primary components form each loop in the input and output loops of LED switching power supplies: filtering capacitors, power switches or rectifiers, and inductors or transformers. These crucial components should be placed adjacently, and their positions adjusted to minimize the length of current paths between them. The ideal design flow for building a switching power supply layout aligns with its electrical design:
<ol type="1">
<li>Place the transformer.</li>
<li>Design the power switch current loop.</li>
<li>Design the output rectifier current loop.</li>
<li>Connect to the control circuit of the AC power supply.</li>
<li>Design the input current source loop and input filter.</li>
</ol>
Conclusion
The proper PCB circuit design is a crucial aspect of LED switching power supplies that significantly impacts their performance and reliability. By understanding the importance of current loop layouts, filtering capacitors, and component arrangements, engineers can effectively minimize electromagnetic interference and enhance the stability and safety of LED power supplies. Implementing the best practices outlined in this blog ensures that PCB design complements the well-designed electrical system, culminating in efficient and reliable LED switching power supplies.
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<title>11 Essential PCB Design Tips for Solar Panel Electronics</title>
<link>https://pcbassemblytech.com/pcb-design-tips-for-solar-panel-electronics/</link>
<dc:creator><![CDATA[PCBA Tech]]></dc:creator>
<pubDate>Mon, 10 Jul 2023 13:34:07 +0000</pubDate>
<category><![CDATA[Technology]]></category>
<guid isPermaLink="false">https://www.pcbassemblytech.com/?p=3797</guid>
<description><![CDATA[When designing solar-powered embedded systems for outdoor applications, it is crucial to consider durability, performance, and energy efficiency. Achieving a…]]></description>
<content:encoded><![CDATA[
When designing solar-powered embedded systems for outdoor applications, it is crucial to consider durability, performance, and energy efficiency. Achieving a balance among these factors is essential for the success of your solar project. By implementing the following 11 PCB design tips, you can enhance your solar-powered devices’ manufacturability and overall effectiveness.
11 Essential PCB Design Tips for Solar Panel Electronics
<ol type="1">
<li>Involve your PCB vendor early: Engaging your electronics manufacturing vendor in the early stages of PCB design is crucial. Their experience and expertise can help identify potential issues that may need to be apparent on paper. Collaboration with your vendor can prevent costly long-term problems, ensuring smooth device manufacturing, performance, and certification approvals.</li>
<li>Consider the efficiency of the solar panel: The efficiency of your solar panel plays a significant role in the overall performance of your electronics. Different types of solar panels, such as monocrystalline, thin film, or polycrystalline, offer varying levels of efficiency. It is essential to confirm the efficiency of the panel you intend to use before proceeding with the PCB design.</li>
<li>Confirm battery and panel sizes: A battery backup system is essential for solar-powered devices that require continuous operation. When designing your solar PCB, consider the duration the system should function when the solar panel’s power is reduced to 0%. Factors like environmental conditions can impact the panel’s performance, so choosing a battery with adequate capacity ensures uninterrupted device operation.</li>
<li>Assess the need for power-intensive modules: Certain applications, such as thermal printers, Wi-Fi, and GSM modules, require higher power consumption. Accurately assessing the power requirements of these modules is crucial for designing a solar panel system that can seamlessly power such components.</li>
<li>Consider firmware architecture: Designing an efficient firmware structure is essential for optimizing energy savings in solar-powered embedded systems. Incorporate features that enable the microcontroller to enter “deep sleep” mode when not in use, prolonging the device’s operational time during unfavorable conditions. Implementing a separate power channel for logistics and peripheral integrated circuits reduces unnecessary power consumption during idle periods.</li>
<li>Build a corrosion-resistant box: Given that solar devices are exposed to the elements, ensuring that the circuit boards inside a solar device are protected from harsh conditions is essential. They provide a corrosion-resistant box with temperature control safeguards against hailstorms, extreme temperature changes, and hurricanes, which can compromise the system’s performance and longevity.</li>
<li>Achieve easy current flow: Optimizing current flow within the solar panel circuit board is crucial for maximizing energy efficiency. Use online calculators to determine the optimal line width that facilitates easy current flow. Additionally, when designing the PCB layout, alternate the wiring directions between consecutive layers to enhance current flow and minimize resistance.</li>
<li>Get your PCB component sizes right: Choosing appropriately sized components during the design stage prevents complications during manufacturing. If space allows, opt for slightly larger components that improve manufacturability. Investing in the right component sizes early on can streamline production and reduce flaws.</li>
<li>Go lean: Lean PCB design reduces engineering, testing, processing, handling, and stock management requirements. Fewer parts lead to cost and assembly time reductions. Complex designs featuring surface mount technology (SMT) on both sides or through-hole components on both sides tend to be costlier. Minimize unnecessary complexity unless it is critical to the product’s functionality.</li>
<li>Choose a suitable surface finish: Selecting the right surface finish is crucial for PCB design. The surface finish should protect the circuitry from corrosion while providing a solderable component surface. Avoid using a RoHS-compliant hot air solder leveling (HASL) finish, as it tends to remove solder from the PCB. Electroless nickel immersion gold (ENIG) is a cost-effective and practical option that offers a flat surface and easy solderability.</li>
<li>Space your PCB component layout appropriately: Proper component placement in the PCB design significantly impacts efficiency and durability. Components placed too close to the edge may be prone to cracking or functional issues. Ensure there is sufficient routing space around components near the edge and throughout the entire PCB layout to facilitate proper wiring and prevent errors that could affect the system’s efficiency.</li>
</ol>
Conclusion: 
Following the 11 PCB design tips above for solar panel electronics, you can improve your solar-powered devices’ manufacturability, performance, and durability. Collaborating with your PCB vendor, considering panel efficiency, confirming battery and panel sizes, and optimizing current flow are essential steps in designing effective solar PCBs. Implementing these tips will help you create robust solar-powered systems capable of withstanding outdoor conditions while maximizing energy efficiency.
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<title>How to Choose Board-to-Board Connectors?</title>
<link>https://pcbassemblytech.com/how-to-choose-board-to-board-connectors/</link>
<dc:creator><![CDATA[PCBA Tech]]></dc:creator>
<pubDate>Fri, 07 Jul 2023 02:11:27 +0000</pubDate>
<category><![CDATA[Technology]]></category>
<guid isPermaLink="false">https://www.pcbassemblytech.com/?p=3794</guid>
<description><![CDATA[This PCB contains multiple connectors that could be used for board-to-board connections or cable assemblies. Anyone who’s ever looked inside…]]></description>
<content:encoded><![CDATA[
This PCB contains multiple connectors that could be used for board-to-board connections or cable assemblies.
Anyone who’s ever looked inside an old desktop computer and unplugged a ribbon cable is familiar with the humble pin header. This connector is a simple but effective way to connect two boards together in a stacked arrangement. In fact, it’s so popular that it’s been used to build add-on shield boards for popular platforms like Arduino and Raspberry Pi, both of which have seen success outside the maker space. In a recent engagement with a client, I was surprised to see how they had stacked up multiple Raspberry Pi boards to run some critical equipment, which shows the importance of board-to-board connectors in these types of modular systems.
Even though pin headers are simple, it doesn’t mean they aren’t useful. However, they aren’t the only option, and there are many board-to-board connector options for high speed/high frequency systems, or for high voltage/high power systems. These connectors find their way into systems as diverse as military equipment to medical equipment. If you’re taking a modular design approach to your next hardware platform and you need to link multiple boards together easily, consider board-to-board connectors instead of cables. There are many cost-effective options on the market that can ensure signal integrity and rugged design in a range of systems.
<h2 class="wp-block-heading">The Many Types of Board-to-Board Connectors</h2>
Board-to-board connectors come in a variety of shapes and sizes to give a modular feel to a multi-board PCB system. There are many types of common board connectors, and different vendors have their own product lines that fall generally into one of the categories listed below:
<ul>
<li>Pin headers: Most designers are familiar with the 1-row or 2-row pin header arrangement with 1 mm pitch. There are variations on this style, including stacked pin headers. Pin headers can be shrouded and keyed (even multi-keyed) to guarantee pinouts match when boards are connected. </li>
<li>Mezzanine connectors: This type of board-to-board connector joins two parallel printed circuit boards in a stacked configuration. There are many mezzanine connector styles. Note that a pin header can be used as a mezzanine connector. </li>
<li>Edge card connectors: This style connector is most commonly known for its use in RAM sticks and COMs/SoMs. Really, it can be used for any board-to-board connection along a board edge, whether with a custom or standardized pinout. </li>
<li>Backplane connectors: This type of connector deserves its own category, both due to its need to accommodate high data rates and very rugged construction.</li>
<li>Standardized connectors: Some connectors may be developed to meet very specific industry standards beyond edge connector styles for add-in cards. Standards organizations that have defined specific connector styles include VITA (for backplanes), PCI-SIG (PCIe cards), IEEE (e.g., 1386 standard for mezzanine), JTAG, PC/104 (square-post pin headers), and others. </li>
</ul>
There are many other connectors that don’t fall into one of the above categories. The image below shows an example of some typical products that fall within these categories.
<img decoding="async" alt="b2bconn-1" src="https://images.ctfassets.net/vne94x762vsn/7AdOg6vHexHk7E4ZQadhPf/6ec8e550490ce87dfc75ef5a3f6d3636/b2bconn-1.png">Some examples of board-to-board connectors.
The image above is just a subset of all the different board-to-board connectors available on the market. Obviously, there are many variations on these connectors with different pin/pad counts, key/shroud styles, mounting styles (SMD vs. through-hole), and specifications. When you’re looking through a vendor’s website or filtering through a parts search engine, there are a few different ways vendors will categorize their parts.
<h3 class="wp-block-heading">Electrical Application</h3>
Within these different types of board-to-board connectors, they may be classified as ruggedized, high speed, high frequency, high current/high power, or some other designation. This is largely marketing speak as there is no universal definition of a high speed connector, high power connector, etc. One important exception is backplane connectors, which are strictly defined in the ANSI/VITA standards, where specific styles pair with different media (copper, fiber, or coaxial cable). Another highly standardized connector style is the IEEE 1386 mezzanine connector.
<h3 class="wp-block-heading">Rugged Application</h3>
As is the case with many other components, vendors will target specific industries with their products and will try to target specific applications in those industries. As a result, you’ll see styles of board-to-board connectors that might be highly ruggedized with hard plastic shielding as they target areas like automotive, aerospace, industrial systems, or power products. In general, you can usually find a ruggedized version of a standard connector that has the same pinout, mounting style, and pitch as its less rugged variant.
<h2 class="wp-block-heading">Selecting Board-to-Board Connectors</h2>
Now we can look at some of the points to consider when <a href="https://octopart.com/blog/archives/2016/10/how-to-choose-a-connector" target="_blank" rel="noopener">selecting board-to-board connectors</a>. First, let’s look at some specifications, then we can think about the advantages of different connector styles.
<h3 class="wp-block-heading">Board-to-Board Connector Specifications</h3>
Board-to-board connectors have some electrical specifications that should be considered beyond just the connector style:
<ul>
<li>Pitch and pin count: Unless you’re designing to a specific application, or you need high speed/high frequency or high current, you’ll probably start by looking at the pitch/pin count required in the connector. With low power and low speed signaling, just about every connector can handle your power requirements while ensuring signal integrity. </li>
<li>Power handling: This is normally quoted as current at a specific voltage per pin. Most connectors can handle a few Amps at typical application voltages. Make sure to check the voltage as it is common to supply both power and data through a cable; you’ll want to make sure your power does not exceed the voltage rating. </li>
<li>Governing standard: Any industry standards on connectors can govern form factor (some examples are discussed above), or they can cover testing and application specifications. Make sure to check these to ensure your connector style will be compliant.</li>
<li>Environmental ratings: Specifications include power variations with humidity cycling, exposure to gases, and testing at high temperature. This gives you a good idea of where the connector can be used to ensure reliability.</li>
<li>Data rate/frequency limit: For high speed data channels, you’ll see a recommended data rate limit, which the vendor will determine through extensive testing. Data rate limits are just a recommendation, and you might be able to get past these in your system. Be sure to test your system thoroughly if you plan to violate a data rate/frequency specification.</li>
<li>Mechanical specifications: High-quality board-to-board connector datasheets may include some data on mechanical shock, vibration, pulling force, or other specs that help a designer understand ruggedness. Note that these may be listed as test results meant to comply with some industry standard.</li>
<li>Form factor: Some board-to-board connectors (like edge connectors) can be rather bulky. Other connectors are specifically designed to have a low profile,  such as the BM20 series of low-profile mezzanine connectors from Hirose. Watch out for the form factor and enclosure requirements in your system.</li>
</ul>
<img decoding="async" alt="b2bconn-2" src="https://images.ctfassets.net/vne94x762vsn/2yXYy5R4SxZ9sQzqqTpT9n/b33ebf8a98b936c49bd676c2b0c3af1b/b2bconn-2.png">The BM20 series of low-profile board-to-board connectors from Hirose has become more popular on some SoMs recently. From the BM20 datasheet.
The various styles shown in the previous section might be a constraining factor as you might need to interface with an existing system, so you won’t have freedom to choose any connector. In many cases, the consideration starts with some electrical or mechanical constraint, followed by choosing the form factor or connector style you need to hit your profile/enclosure requirements.
If you do have freedom to choose your connector style and form factor, there are some advantages to each type of connector that should be considered.
<h3 class="wp-block-heading">Advantages of Some Board-to-Board Connector Styles</h3>
With so many styles of board-to-board connectors on the market, it’s impossible to provide a complete comparison between every type of connector. However, there are some basic points to understand about different connector styles that reveal their advantages or disadvantages in different systems. 
<h4 class="wp-block-heading">Edge Connectors</h4>
Edge connectors use sliding contacts to make an electrical connection, and these can eventually wear away after making repeated connections. Wear can happen on the card side or the receptacle side. If the board will need to be repeatedly connected and removed, alternative styles may be a better choice as many of these will have a longer contact lifetime.
<img decoding="async" alt="1440x720 2" src="https://images.ctfassets.net/vne94x762vsn/5X8p7hKJGj2ArH42EjMGWJ/4a52605f72a770f79c21edb0334324ab/1440x720_2.png">We can see wear on the gold contacts on this edge connector.
<h4 class="wp-block-heading">Fully-Shrouded or Coaxial Style</h4>
Some connectors have a coaxial style that enables high power transfer, provides shielding, and advantages for RF systems (see below). Fully shrouded connectors are ideal for higher power applications and will have much higher current ratings without being excessively large on the board. This is a better option than a pin header, which may have as low as 1 A current rating and no useful high-speed/RF data.
<h4 class="wp-block-heading">Low-profile Horizontal Connector Styles</h4>
Your connector orientation may allow for parallel boards, but the board might be able to be removed horizontally rather than vertically. For example, the Hirose connector shown above requires vertical removal, but there are edge connectors and mezzanine connectors that horizontal insertion/removal while maintaining a very low profile. This can be invaluable in low-profile applications where an add-in card needs to be accessed.
<img decoding="async" alt="1440x720 3 (1)" src="https://images.ctfassets.net/vne94x762vsn/3FZctZRLHuUX49mEyqlI17/65be373c2dba71359b0d6e1c3304bcf0/1440x720_3__1_.png">This edge connector is often used for PCIe add-in cards
<h4 class="wp-block-heading">Pin Header Blocks</h4>
If you’re not worried about high current, high isolation, or highly precise signal integrity, stackable pin headers are a great way to add multiple levels of modularity to your system. Pin header blocks can be selected so that they are stackable, which allows multiple cards to be placed on a bus or allows power to be provided to multiple boards in parallel. If you need data access at every module, make sure the pinouts match throughout the pin header stack.
<h3 class="wp-block-heading">What About High Speed and High Frequency?</h3>
At high speeds/high frequencies reaching to Gbps/GHz levels, signal integrity becomes an important point to consider when selecting board-to-board connectors. Look for some of the following metrics in datasheets or from your manufacturer’s support pages:
<ul>
<li>Impedance: RF connectors with coaxial topology will have a specified impedance as they will need to interface with a specific system impedance. The impedance specification is valid up to the stated bandwidth, which might be a -3 dB frequency.</li>
<li>S-parameter data: If you want to do any kind of simulation with your connectors, then you’ll need S-parameter data. This is quite important with technologies like PAM4, SerDes channels, or newer high speed signaling standards (PCIe, GDDR6, etc.) as these simulations are an important part of system validation. </li>
<li>Pin-to-pin isolation: RF board-to-board connectors may have all pins entirely shielded, which is not always the case for other connector styles. These connectors will have high isolation and low pin count. They also tend to be bulkier. Some of these board-to-board connectors will have available cable connector variants.</li>
</ul>
When you need to filter through multiple vendors and find specific types of board-to-board connectors, use the <a href="https://octopart.com/blog/archives/2018/03/machine-learning-categorize-parts" rel="nofollow noopener" target="_blank">advanced search and filtration features</a> in Octopart. The electronics search engine features in Octopart can help you choose connectors by industry, technical specifications, signaling standard, and many other filters to suit your needs. You can also access distributor pricing data, parts inventory, parts specifications, and CAD data, and it’s all freely accessible in a user-friendly interface.
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