**PCB circuit board**, also known as a **Printed Circuit Board (PCB)**, facilitates circuit connections and the functional integration of electronic components, and it plays a crucial role in power supply circuit design.
1. **Basic Rules of Component Layout**
1. Layout components based on circuit modules, where related circuits that perform similar functions are grouped into a module. Within each module, components should be placed close together, and digital circuits should be separated from analog circuits.
2. Avoid placing any components or devices within 1.27mm of non-mounting holes such as positioning holes and standard holes. Additionally, maintain a distance of 3.5mm (for M2.5) and 4mm (for M3) around mounting holes such as screws.
3. Prevent placing via holes directly beneath horizontally mounted resistors, inductors (through-hole), electrolytic capacitors, and other components to avoid short-circuiting the vias and component housing after wave soldering.
4. Maintain a distance of 5mm between the edge of a component and the edge of the board.
5. Ensure that the distance between the edge of a mounting component pad and the edge of an adjacent component is greater than 2mm.
6. Metal shell components and metal parts (such as shielding boxes) should not come into contact with other components or be close to printed traces and pads; maintain a spacing of at least 2mm. The distance from the edges of positioning holes, fastener installation holes, oval holes, and other non-standard holes to the board edge should be greater than 3mm.
7. Keep heating elements away from wires and heat-sensitive components; distribute high-heat devices evenly across the board.
8. Position power sockets around the perimeter of the printed board whenever possible, and ensure that power sockets and their corresponding bus bar terminals are on the same side. Avoid placing power sockets and other soldered connectors between connectors to facilitate easy soldering and power cable management. The spacing of power sockets and soldered connectors should allow for convenient plugging and unplugging of power plugs.
9. Arrangement of other components:
All IC components should be aligned on one side, and the polarity of polar components must be clearly marked. The same printed board should not have polarity indicators in more than two directions. When two directions are present, they must be perpendicular to each other.
10. The board surface wiring should be dense and uniform. If there is a significant density difference, fill it with mesh copper foil, ensuring the grid is greater than 8mil (or 0.2mm).
11. No through-holes should be present on the PCB patch pads to prevent solder paste loss and false soldering of components. Important signal lines must not pass between socket pins.
12. The patch should be aligned on one side, with consistent character and packaging directions.
13. Polarized devices should be oriented consistently with the polarity markings on the same board.
Two, component wiring rules
1. Draw the wiring area within 1mm from the PCB edge and around mounting holes; wiring is prohibited in these areas.
2. Power cords should be as wide as possible, not less than 18mil; signal line widths should not be less than 12mil; CPU input and output lines should not be less than 10mil (or 8mil); line spacing should not be less than 10mil.
3. Normal vias should be no less than 30mil.
4. Dual in-line: 60mil pad, 40mil aperture; 1/4W resistor: 51*55mil (0805 surface mount); 62mil pad, 42mil aperture for in-line; Infinite capacitor: 51*55mil (0805 surface mount); for in-line, the pad should be 50mil and the aperture 28mil.
5. The power line and ground line should be as radial as possible, and signal lines should avoid looping.
How to improve anti-interference ability and electromagnetic compatibility when developing electronic products with processors?
The following systems require special attention to anti-electromagnetic interference:
(1) Systems with extremely high microcontroller clock frequencies and fast bus cycles.
(2) Systems containing high-power, high-current drive circuits, such as spark-producing relays and high-current switches.
(3) Systems with weak analog signal circuits and high-precision A/D conversion circuits.
1. **Basic Rules of Component Layout**
1. Layout components based on circuit modules, where related circuits that perform similar functions are grouped into a module. Within each module, components should be placed close together, and digital circuits should be separated from analog circuits.
2. Avoid placing any components or devices within 1.27mm of non-mounting holes such as positioning holes and standard holes. Additionally, maintain a distance of 3.5mm (for M2.5) and 4mm (for M3) around mounting holes such as screws.
3. Prevent placing via holes directly beneath horizontally mounted resistors, inductors (through-hole), electrolytic capacitors, and other components to avoid short-circuiting the vias and component housing after wave soldering.
4. Maintain a distance of 5mm between the edge of a component and the edge of the board.
5. Ensure that the distance between the edge of a mounting component pad and the edge of an adjacent component is greater than 2mm.
6. Metal shell components and metal parts (such as shielding boxes) should not come into contact with other components or be close to printed traces and pads; maintain a spacing of at least 2mm. The distance from the edges of positioning holes, fastener installation holes, oval holes, and other non-standard holes to the board edge should be greater than 3mm.
7. Keep heating elements away from wires and heat-sensitive components; distribute high-heat devices evenly across the board.
8. Position power sockets around the perimeter of the printed board whenever possible, and ensure that power sockets and their corresponding bus bar terminals are on the same side. Avoid placing power sockets and other soldered connectors between connectors to facilitate easy soldering and power cable management. The spacing of power sockets and soldered connectors should allow for convenient plugging and unplugging of power plugs.
9. Arrangement of other components:
All IC components should be aligned on one side, and the polarity of polar components must be clearly marked. The same printed board should not have polarity indicators in more than two directions. When two directions are present, they must be perpendicular to each other.
10. The board surface wiring should be dense and uniform. If there is a significant density difference, fill it with mesh copper foil, ensuring the grid is greater than 8mil (or 0.2mm).
11. No through-holes should be present on the PCB patch pads to prevent solder paste loss and false soldering of components. Important signal lines must not pass between socket pins.
12. The patch should be aligned on one side, with consistent character and packaging directions.
13. Polarized devices should be oriented consistently with the polarity markings on the same board.
Two, component wiring rules
1. Draw the wiring area within 1mm from the PCB edge and around mounting holes; wiring is prohibited in these areas.
2. Power cords should be as wide as possible, not less than 18mil; signal line widths should not be less than 12mil; CPU input and output lines should not be less than 10mil (or 8mil); line spacing should not be less than 10mil.
3. Normal vias should be no less than 30mil.
4. Dual in-line: 60mil pad, 40mil aperture; 1/4W resistor: 51*55mil (0805 surface mount); 62mil pad, 42mil aperture for in-line; Infinite capacitor: 51*55mil (0805 surface mount); for in-line, the pad should be 50mil and the aperture 28mil.
5. The power line and ground line should be as radial as possible, and signal lines should avoid looping.
How to improve anti-interference ability and electromagnetic compatibility when developing electronic products with processors?
The following systems require special attention to anti-electromagnetic interference:
(1) Systems with extremely high microcontroller clock frequencies and fast bus cycles.
(2) Systems containing high-power, high-current drive circuits, such as spark-producing relays and high-current switches.
(3) Systems with weak analog signal circuits and high-precision A/D conversion circuits.
