Power Supply Rejection Ratio (PSRR)

Last modified by Microchip on 2023/11/09 08:59

A battery-powered application can see a change in the power supply voltage of several hundreds of millivolts over the life of a product. Moreover, the op-amp is also often supplied from noisy lines and must, therefore, reject the noise adequately. For these reasons, it is important to know how a change or noise in the power supply manifests itself at the output of an op-amp.

It quantifies the amplifier’s sensitivity to power supply changes. Ideally, the Power Supply Rejection Ratio (PSRR) should be infinite. In other words, the power supply changes do not affect the output. Typical specifications for the PSRR of an amplifier range from 60 dB to 100 dB.

PSRR Diagram

The accompanying image shows the MCP601 PSRR specification.

PSRR Specifications