1. PCB (Printed Circuit Board), known in Chinese as 印刷电路板, is a crucial electronic component and one of the most versatile products in electronics, exhibiting remarkable longevity.
2. Over the past 20 years of reform and opening up, the PCB industry has rapidly developed with the introduction of advanced foreign technology and equipment, leading to significant advancements in single-sided, double-sided, and multi-layer boards.
3. The domestic PCB industry has evolved from small-scale beginnings to a large, rapidly growing sector, with an annual growth rate of approximately 20%.
4. In terms of output, China’s PCB industry has transitioned from focusing on single-sided and double-sided boards to multi-layer boards, with layers increasing from 4-6 to 6-8 or more.
5. As a technological breakthrough, PCBs offer flexible design, stable electrical performance, and superior economic benefits, sparking interest in their design fundamentals among many customers.
6. Multi-layer printed boards are those with more than two layers, consisting of conductive paths on several insulating substrates, and pads for assembling and soldering electronic components.
7. Proper insulation is crucial, making it essential to approach printed board design with caution and adhere to necessary principles.
Here’s a revised version of your article with improved clarity and style:
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**Check the schematic diagram carefully:** The design of any printed circuit board (PCB) is inherently linked to the schematic diagram. The accuracy of the schematic is the foundation for the correctness of the PCB design. Therefore, before starting the PCB design, it is crucial to thoroughly and repeatedly verify the schematic’s signal integrity to ensure proper device connections.
**Component selection:** Choosing components is a critical step in PCB design. Devices with the same functions and parameters may vary in packaging, and different packaging results in different solder hole (pad) configurations. Thus, before beginning PCB design, it is essential to finalize the packaging form of each component.
**Basic requirements for multi-layer PCB design:**
1. **Determination of board shape, size, and number of layers:**
A PCB must fit with other structural components. Hence, the board’s shape and size should align with the product’s structure. From a production perspective, simplicity is preferred; typically, a rectangular shape with a moderate aspect ratio is ideal for ease of assembly, enhanced production efficiency, and reduced labor costs.
The number of layers depends on the circuit’s performance requirements, board size, and circuit density. Four-layer and six-layer boards are commonly used. For instance, a four-layer board includes two signal layers (component and soldering surfaces), a power layer, and a ground layer.
The layers of a multi-layer board should be symmetrical and preferably in multiples of four (e.g., four, six, or eight layers). Asymmetrical lamination can lead to warping, particularly in surface-mounted multi-layer boards, which requires careful attention.
2. **Position and placement direction of components:**
The placement and orientation of components should first follow the circuit’s logical flow. Proper placement is crucial for PCB performance, particularly for high-frequency analog circuits, which demand precise placement to avoid interference.
3. **Requirements for wire layout and wiring area:**
Typically, multi-layer PCB wiring is based on circuit functions. On outer layers, more wiring is done on the soldering surface than the component surface, which aids in maintenance and heat dissipation. Inner layers often carry thin, dense wires and sensitive signal traces. Large copper areas should be evenly distributed across layers to minimize warping and ensure uniform plating. To prevent damage and short circuits during machining, maintain a minimum distance of 50 mils between the conductive patterns and the board edges.
4. **Requirements for wire orientation and line width:**
Separate power, ground, and signal layers to minimize interference. Lines on adjacent layers should be perpendicular, diagonal, or curved, avoiding parallel lines to reduce coupling and interference. For small signal circuits, keep wire lengths short to lower resistance and interference.
5. **Drilling size and pad requirements:**
The diameter of component holes should match the pin size, with a slight additional margin (10-30 mils) to accommodate assembly. Pad diameter should be at least the hole diameter plus 18 mils. Via hole diameter depends on board thickness, with a typical ratio of hole diameter to board thickness ≤ 5:1. The via pad diameter should be at least 12 mils larger than the via hole diameter.
6. **Requirements for power supply layer, stratum zone, and vias:**
Multi-layer boards require at least one power layer and one ground layer. Power layers must be partitioned and isolated, with partition lines generally ranging from 20-80 mils in width, thicker for higher voltages.
7. **Requirements for safety clearance:**
Safety distances should meet electrical safety standards. Outer conductor spacing should not be less than 4 mils, and inner conductor spacing should also be at least 4 mils. Where possible, increase spacing to enhance manufacturing yield and reduce the risk of board failure.
8. **Improving the board’s anti-interference capability:**
Enhance the board’s resistance to interference by:
A. Placing filter capacitors near each IC’s power and ground pins, typically with values of 473 or 104.
B. Adding shielding around sensitive signals and minimizing nearby wiring.
C. Selecting a reasonable grounding point.
**Multi-layer PCB outsourcing processing requirements:**
PCB processing is usually outsourced. Ensure that drawings provided for outsourcing are accurate and clear. Specify material choices, lamination order, board thickness, tolerance requirements, and processing technology. Export GERBER files in RS274X format to facilitate automatic data entry by CAM systems, reducing manual input errors and increasing consistency.
In addition to the aforementioned design requirements, consider external connections, optimized component placement, metal connections, electromagnetic protection, and heat dissipation. The PCB connector is a crucial component in this process. While the design is important, selecting high-quality connectors should not be overlooked.
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I hope this revision meets your needs!
2. Over the past 20 years of reform and opening up, the PCB industry has rapidly developed with the introduction of advanced foreign technology and equipment, leading to significant advancements in single-sided, double-sided, and multi-layer boards.
3. The domestic PCB industry has evolved from small-scale beginnings to a large, rapidly growing sector, with an annual growth rate of approximately 20%.
4. In terms of output, China’s PCB industry has transitioned from focusing on single-sided and double-sided boards to multi-layer boards, with layers increasing from 4-6 to 6-8 or more.
5. As a technological breakthrough, PCBs offer flexible design, stable electrical performance, and superior economic benefits, sparking interest in their design fundamentals among many customers.
6. Multi-layer printed boards are those with more than two layers, consisting of conductive paths on several insulating substrates, and pads for assembling and soldering electronic components.
7. Proper insulation is crucial, making it essential to approach printed board design with caution and adhere to necessary principles.
Here’s a revised version of your article with improved clarity and style:
—
**Check the schematic diagram carefully:** The design of any printed circuit board (PCB) is inherently linked to the schematic diagram. The accuracy of the schematic is the foundation for the correctness of the PCB design. Therefore, before starting the PCB design, it is crucial to thoroughly and repeatedly verify the schematic’s signal integrity to ensure proper device connections.
**Component selection:** Choosing components is a critical step in PCB design. Devices with the same functions and parameters may vary in packaging, and different packaging results in different solder hole (pad) configurations. Thus, before beginning PCB design, it is essential to finalize the packaging form of each component.
**Basic requirements for multi-layer PCB design:**
1. **Determination of board shape, size, and number of layers:**
A PCB must fit with other structural components. Hence, the board’s shape and size should align with the product’s structure. From a production perspective, simplicity is preferred; typically, a rectangular shape with a moderate aspect ratio is ideal for ease of assembly, enhanced production efficiency, and reduced labor costs.
The number of layers depends on the circuit’s performance requirements, board size, and circuit density. Four-layer and six-layer boards are commonly used. For instance, a four-layer board includes two signal layers (component and soldering surfaces), a power layer, and a ground layer.
The layers of a multi-layer board should be symmetrical and preferably in multiples of four (e.g., four, six, or eight layers). Asymmetrical lamination can lead to warping, particularly in surface-mounted multi-layer boards, which requires careful attention.
2. **Position and placement direction of components:**
The placement and orientation of components should first follow the circuit’s logical flow. Proper placement is crucial for PCB performance, particularly for high-frequency analog circuits, which demand precise placement to avoid interference.
3. **Requirements for wire layout and wiring area:**
Typically, multi-layer PCB wiring is based on circuit functions. On outer layers, more wiring is done on the soldering surface than the component surface, which aids in maintenance and heat dissipation. Inner layers often carry thin, dense wires and sensitive signal traces. Large copper areas should be evenly distributed across layers to minimize warping and ensure uniform plating. To prevent damage and short circuits during machining, maintain a minimum distance of 50 mils between the conductive patterns and the board edges.
4. **Requirements for wire orientation and line width:**
Separate power, ground, and signal layers to minimize interference. Lines on adjacent layers should be perpendicular, diagonal, or curved, avoiding parallel lines to reduce coupling and interference. For small signal circuits, keep wire lengths short to lower resistance and interference.
5. **Drilling size and pad requirements:**
The diameter of component holes should match the pin size, with a slight additional margin (10-30 mils) to accommodate assembly. Pad diameter should be at least the hole diameter plus 18 mils. Via hole diameter depends on board thickness, with a typical ratio of hole diameter to board thickness ≤ 5:1. The via pad diameter should be at least 12 mils larger than the via hole diameter.
6. **Requirements for power supply layer, stratum zone, and vias:**
Multi-layer boards require at least one power layer and one ground layer. Power layers must be partitioned and isolated, with partition lines generally ranging from 20-80 mils in width, thicker for higher voltages.
7. **Requirements for safety clearance:**
Safety distances should meet electrical safety standards. Outer conductor spacing should not be less than 4 mils, and inner conductor spacing should also be at least 4 mils. Where possible, increase spacing to enhance manufacturing yield and reduce the risk of board failure.
8. **Improving the board’s anti-interference capability:**
Enhance the board’s resistance to interference by:
A. Placing filter capacitors near each IC’s power and ground pins, typically with values of 473 or 104.
B. Adding shielding around sensitive signals and minimizing nearby wiring.
C. Selecting a reasonable grounding point.
**Multi-layer PCB outsourcing processing requirements:**
PCB processing is usually outsourced. Ensure that drawings provided for outsourcing are accurate and clear. Specify material choices, lamination order, board thickness, tolerance requirements, and processing technology. Export GERBER files in RS274X format to facilitate automatic data entry by CAM systems, reducing manual input errors and increasing consistency.
In addition to the aforementioned design requirements, consider external connections, optimized component placement, metal connections, electromagnetic protection, and heat dissipation. The PCB connector is a crucial component in this process. While the design is important, selecting high-quality connectors should not be overlooked.
—
I hope this revision meets your needs!
