PCB Design Tips to Reduce Electromagnetic Interference Part2
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.
11.Single-sided board and double-sided board access to power and grounding by single point, thus power lines and ground lines should be as thick as possible.
12.Keep clock, bus wire and chip select signals far away from I/O lines and connectors.
13.Keep analog voltage input line and VREF away from the digital signal lines, especially the clock.
14.For A/D components, the digital part and the analog part should be unified rather than cross.
15.Both component’s pins and decoupling capacitor’s pins are as short as possible.
16.The key lines should be as thick as possible with protection on both sides, while high-speed lines should be short and straight.
17.Don't keep noise-sensitive lines parallel with high-current, high-speed switch lines.
18.Do not route below quartz crystals and noise sensitive components.
19.No current loop around weak signal circuit or low frequency circuit.
20.Do not form a signal loop, if inevitable, keep the loop area as small as possible.
21.One decoupling capacitor per integrated circuit. Add a small high-frequency bypass capacitor to the edge of each electrolytic capacitor.
22.Use high-capacity tantalum capacitors or poly condenser capacitors instead of electrolytic capacitors for charging and discharging storage capacitor. When using tubular capacitors, the housing should be grounded.