Circuit Board Decoupling Information

Decoupling capacitors are an important part of any digital printed circuit board design. These capacitors are connected between power and power return conductors to help stabilize the voltage delivered to active digital devices. When there is a sudden change in the current drawn by a particular device, decoupling capacitors provide a local source of charge so that current can be supplied quickly without causing the voltage on the power pins to dip suddenly. Boards with inadequate decoupling suffer from excessive power bus noise, which may cause signal integrity or EMC problems affecting the reliability of the product.

The following information may be useful to anyone wishing to optimize their printed circuit board decoupling.