Application Information

TS4975

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4.7

Notes on PSRR measurement

What is PSRR?

The PSRR is the Power Supply Rejection Ratio. The PSRR of a device is the ratio between a

power supply disturbance and the result on the output. In other words, the PSRR is the ability of

a device to minimize the impact of power supply disturbance to the output.

How we measure the PSRR?

The PSRR was measured according to the schematic shown in

Figure 62. PSRR measurement schematic

Principles of operation

●

●

●

The PSRR value for each frequency is calculated as:

RMS is a rms selective measurement.

PSRR

20Log

RMS

Out put

()

RMS

V

ri pple

()

--------------------------------- dB

()

=