9.1 Power-Supply Decoupling Techniques and Recommendations

Power-supply decoupling is a critical aspect of any high-performance amplifier design. Careful decoupling provides higher quality ac performance. The following guidelines ensure the highest level of performance.

1. Place decoupling capacitors as close to the power-supply inputs as possible, with the goal of minimizing the inductance.
2. Placement priority should put the smallest valued capacitors closest to the device.
3. Use of solid power and ground planes is recommended to reduce the inductance along power-supply return current paths (with the exception of the areas underneath the input and output pins as noted below).
4. A bulk decoupling capacitor is recommended (6.8 μF to 22 μF) within 1 inch, and a ceramic (0.1 μF) within 0.1 inch of the power input pins.