About the PSRR frequency range!

[gdhp]

HI all

I have a puzzle about the PSRR frequency range. For normal analog block, such as

OPAMP, BG, when we consider its psrr, how is the power ripple frequency range is

considered. 1K is enough?

I thought on the chip( and also board), a big cap is between the power and ground.

So only very low frequency ripple on power supply should be considered. Is it ok?

What is the maximun frequency should be considered?

Thanks!
gdhp

 

[waxtomato]

Actually, the on chip CAP is normally not enough. People often apply 0.1u ~ 10u cap on PCB board .

I often get power noise > 20kHz when I test

 

[gdhp]

waxtomato
So you mean that when i consider the psrr frequency range of chip, the frequency should between 0-20k?

 

[strennor]

Hi,

Are you designing audio chips?

The datasheet only has spec of 1k, but has PSRR figures upto 20k. I think you should think about it based on your application.