PCB and circuit anti-interference measures (I)

The PCB anti-interference design is closely related to the specific circuit. Here, a few common measures of PCB anti-interference design are given.

1. Power cord design:

According to the size of printed circuit board current, increase the power line width and reduce the loop resistance. At the same time, make the direction of power cord, ground wire and data transmission consistent, which helps to enhance the anti-noise ability.

2. Principles of ground wire design:

(1) the digital and the analog are separated. If there are both logic and linear circuits on the circuit board, separate them as much as possible. For low frequency circuits, single point parallel grounding should be used as far as possible. When the actual wiring is difficult, partial parallel grounding can be followed. The high frequency circuit should adopt multi-point series grounding, the ground line should be short and lease, and the large area grid ground foil should be used as far as possible around the high frequency components.

(2) the ground wire should be as thick as possible. If the ground wire is used with a very strong line, the ground potential changes with the current, so that the anti-noise performance. The grounding wire should therefore be bolded so that it can pass three times the allowable current on the board. If possible, the ground wire should be above 2~3mm.

(3) the ground wire constitutes a closed loop. The grounding circuit of the printed board composed of digital circuit can improve the anti-noise ability.