Electromagnetic Compatibility Design of Mobile Phone PCB (1)

Electromagnetic compatibility refers to the ability of electronic equipment to work harmoniously and effectively in various electromagnetic environments. The purpose of electromagnetic compatibility design is to enable electronic equipment to suppress various external interferences, so that electronic equipment can work normally in a specific electromagnetic environment, and at the same time reduce the electromagnetic interference of electronic equipment to other electronic equipment.

1. Select a Reasonable Wire Width

Since the impulse interference produced by the transient current on the printed wires is mainly caused by the inductive components of the printed wires, the inductance of the printed wires should be minimized. The inductance of the printed wire is proportional to its length and inversely proportional to its width, so short and precise wires are beneficial to suppress interference. Clock traces, signal lines of row drivers or bus drivers often carry large transient currents and traces should be kept as short as possible. For discrete component circuits, when the width of the printed wire is about 1.5mm, it can fully meet the requirements. For integrated circuits, the width of the printed wire can be selected between 0.2 and 1.0 mm.

2. Adopt The Correct Wiring Strategy

The use of equal wiring can reduce the wire inductance, but the mutual inductance and distributed capacitance between the wires will increase. If the layout allows, it is best to use a well-shaped mesh wiring structure. The specific method is to route horizontally on one side of the printed board and vertically on the other. They are then connected with metalized holes at the cross holes.

3. In order to suppress the crosstalk between the wires of the printed board, the long-distance and equal wiring should be avoided as much as possible when designing the wiring, and the distance between the wires should be widened as much as possible. cross. Setting a grounded trace between some signal lines that are very sensitive to interference can effectively suppress crosstalk.