A lot of regulator datasheets give a figure of Power Supply Rejection Ration in decibals. I understand that a high PSRR is good, but how and where does it help me?
For instance, suppose I have a regulated wall-wart power supply that outputs 5V but with about 20 mV noise imposed upon it – let's further assume that the noise is most significant at around 50 kHz.
Would a regulator with 90 db PSRR from 20kHz to 1MHz help me reject that noise?
Let's further assume that I'm measuring voltage with an Instrumenation Amp + ADC (i.e. the In. Amp is driving the ADC). Would a high PSRR generally help me? (I know it probably depends upon a lot of factors but I'm talking about the general situation).