We use cookies. They help to improve your interaction with the site.
Electronics news

Power planes, design guidelines

Ground and power planes are large areas in a PCB design.

Power planes bring the supply voltage to the various components on the board, helping to distribute power evenly across the PCB, thereby reducing voltage drop and providing stable power.

Ground planes help reduce noise and EMI by providing a low impedance path for return currents, thereby improving and maintaining signal integrity. Combined with power planes, they improve power delivery and help prevent outages.

Any two adjacent layers on a PCB naturally form a capacitor due to the proximity of conductive elements and dielectric material between them. This process involves the signal trace and power plane layers, which can cause problems if not accounted for in the PCB design.

If it is necessary or desirable to physically separate the AGND (analog ground) and DGND (digital ground) areas, designers should route digital signals only over a suitable digital reference plane. Similarly, analog traces should be placed over the analog GND (ground) plane to prevent EMI and crosstalk problems between the two areas.

In the case of isolated power converters, the primary and secondary GND networks should be connected in different ways - for example, by using a very high rated protection capacitor so that noise from the output side is returned to the input side through the capacitor while maintaining an isolated barrier.