PCB Design Tips to Reduce Electromagnetic Interference

PCB design becomes more difficult since electronic equipment have been more sensible and required excellent capability to reduce noise and electromagnetic interference. Thus, how to improve the design becomes one of the key issues that many engineers are concerned about. This article describes some tips for reducing noise and electromagnetic interference when designing PCB boards.

1.High-speed chips are used in the key areas.

2.To reduce the upper and lower edge of the control circuit toggle rate, you can string a resistor.

3.Use the lowest frequency clock that meets system requirements.

4.The clock generator is as close as possible to the device using the clock. Quartz crystal oscillator housing shall be grounded.

5.Use the ground wire to enclose the clock area; the clock line should be short as far as possible.

6.I/O driver circuit should be as close to the board edge as possible. Signals should be filtered when entering the printed circuit board, so as signals from the high noise area. At the same time, it is necessary to use string termination resistor approach to reduce the signal reflection.

7.MCD unused end shall be connected to ground or defined as the output end.

8.Don’t keep the input end of gate circuit unconnected; positive input of unused op amp shall be grounded, while negative input should  be connected to the output end.

9.Printed circuit board should use the 45-degree fold line instead of the 90 one in order to reduce the launch and coupling of high-frequency signals.

10.Areas on printed circuit boards should be divided by the frequency and current characteristics of the switch; keep enough distance between noisy components and non-noisy components.