About regulator's psrr

[Alan_Nesta]

I have made a regulator, which can drive 100mA current and 400pF capacitance, so the output device is large, and with Miller compesation(about 20pF) the PSRR+ is bad! only 70-80dB@dc and about 10dB@1MHz
how can i correct this?
Thank you

 

[babbage]

Maybe you should give out the more detailed information about your linear reg?

 

[sunking]

Yes, the psrr of this kind of regulator is like that.

If you wish to enlarge the pssr, there is some special circuit for it.

https://users.ece.gatech.edu/rincon-mora/patents/p6304131.htm

 

[tsanlee]

70-80 dB@DC is a good spec.
The normal spec. of LDO is olny 60-70dB



The PSRR in high frequency alway indue a signal (psrr ) from power by parasitic cap. if you will reduce psrr ,you must care it.

 

[qutang]

at high frequency, the psrr is bad! mostly, we test it at lowfrequency.

 

[Alan_Nesta]

no figure in the document
so can not understand it
can you send me a full copy?
alan_nesta@163.com
yhank you!