Does your PCB's EMI meet the standard?
Tip1: Common mode EMI interference source
- In the power layer with a low value of the inductor, the inductance of the synthesis of the transient signal will be reduced, the common mode EMI to reduce.
- Reduce the length of the power supply to the IC power supply pin.
- Use 3-6 mil PCB layer spacing and FR4 dielectric material.
Tip2: Electromagnetic shielding
- try to put the signal on the same PCB layer, and close to the power layer or ground plane.
- The power plane should be as close as possible to the ground plane
Tip3: the layout of the parts (different layout will affect the circuit interference and anti-jamming capability)
(Such as demodulation circuits, high-frequency amplifying circuits and mixing circuits, etc.), which separates the strong and weak electrical signals in this process, and the digital and analog signal circuits are separated
- The filter network of each part of the circuit must be connected in the near future, which not only can reduce the radiation, which can improve the anti-interference ability of the circuit and reduce the chance of being disturbed.
- Disruptive parts should be avoided in the layout of the interference source, such as data processing board CPU interference and so on.
Tip4: wiring considerations (unreasonable wiring will cause cross-interference between signal lines)
- can not have the border close to the PCB board frame, so as to avoid disruption caused by the production.
- the power cord should be wide and the loop resistance will be reduced.
- the signal line is as short as possible and the number of vias is reduced.
- Corner wiring can not be used in the right angle method, should be 135 ° angle is better.
Reduce the electromagnetic interference is an important part of pcb manufacturer in china and the PCB board design, as long as the design of more to this point of thinking, the product naturally in the test, such as EMC test more qualified.