Design Principles of Camera Module Circuit Boards

The design of the camera module PCB needs to consider multiple aspects, and below are some main design principles:

1.Performance Principles.

Signal Integrity: When routing high-speed differential signals such as MIPI, adjacent differential signal pairs must be isolated by GND pins. If it's to drill holes, the distance between differential pairs should be at least 15mil, and the entire group should be surrounded by a ground. Ground vias be placed every 200mil along the ground line. When changing layers with differential lines, a pair of return ground vias should be added nearby. space permits, strict grounding of the signal should be enforced to reduce crosstalk between signals and ensure signal transmission quality.

Power Integrity: Decoupling capacitors the camera connection seat's AVDD/DOVDD/DVDD power supplies should be placed as close as possible to the camera connection seat. These capacitors not be omitted to ensure power stability and reduce the impact of power noise on the circuit.

Electromagnetic Compatibility: The camera should be kept away from high-power devices, such as GSM antennas, to avoid interference. Elements with strong radiation electromagnetic fields and those sensitive to electromagnetic induction should be kept apart, or a shielding cover be considered for protection.

2.Component Layout Principles.

Functional Zoning: Arrange the position of each functional circuit unit according to the signal flow. Center around the components of each functional circuit, arrange them locally, and ensure the signal flow is smooth and consistent, generally from left to right or top to bottom.

Reasonableacing: All components should be placed on the same side of the PCB, and only when the top layer is too crowded, some low-height and low-heat can be placed on the bottom layer. Components should maintain reasonable spacing to avoid mutual compression or collision, preventing short circuits and electromagnetic interference. Components located at the edge the board should be at least two board thicknesses away from the edge.

Compliance with Mechanical Structure Requirements: Components that need frequent replacement should be easy to replace and adjustable components should be easy to adjust. For adjustable elements like potentiometers, variable capacitors, adjustable inductors, and micro switches, their layout comply with the overall structure requirements. If they need to be adjusted from outside the machine, their position should correspond to the adjustment knob on the machine panel; if need to be adjusted inside the machine, they should be placed in a convenient location on the PCB for adjustment.

3.Wiring Principles.

Wiring Rules: When conditions permit, use wider lines instead of narrower ones to reduce resistance and inance, thereby minimizing signal attenuation and electromagnetic radiation. High voltage and high-frequency lines should be smooth, without sharp corners or right-angle turns, to prevent signal reflection electromagnetic leakage. Ground lines should be as wide as possible, preferably with large-area copper plating, to reduce ground impedance and enhance interference resistance.

Isolation and: Different types of signals, such as input/output, AC/DC, strong/weak signals, high/low frequency, high/low voltage, etc., be routed linearly and separately to prevent mutual interference. The best route is a straight line.

4. Thermal Design Principles.

Heat Dissipation Design: For heatenerating components, such as high-power chips, high-power tubes, resistors, etc., they should be placed in positions favorable for heat dissipation, and if, a separate heat sink or small fan can be set up. When components are placed on both sides, heat-generating components are generally not placed on the bottom.

Thermal Isolation: Temperature-sensitive components should be close to the measured components and away from high-temperature areas to avoid being affected by other heat-generating, which could cause erroneous operation.

5. Manufacturing and Reliability Principles.

Manufacturing Requirements: Consider the manufacturing process and assembly process of the PCB, such as package type of the components, welding method, position and size of the installation holes, etc., to ensure that the circuit board can be smoothly manufactured and assembled. diameter and spacing of ordinary positioning holes should meet certain tolerance requirements to ensure positioning accuracy.

Reliability Design: Components should be evenly distributed across the board to avoid overheating, stress concentration, and other issues, thereby enhancing the reliability and stability of the product. For some key components or easily damaged components, redundancy design or protection circuits can be used to enhance system reliability.