evaluation of PSRR in cadence spectre

[bharathr87]

How do u find the PSRR in cadence spectre through simulation? you have to give an AC signal at Vdde right?and after that how do you find the value of PSRR?

 

[mengcy]

see the ac gain of the output voltage.
that is the ac gain Vout/Vdd,named PSR.
if you want to know PSRR,you must simulate the gain of Vout/Vin.

 

[bharathr87]

how to find the ac gain of the o/p...can u find it frm the ac gain plot?

 

[mmic1978]

see the ac gain of the output voltage.
that is the ac gain Vout/Vdd,named PSR.
if you want to know PSRR,you must simulate the gain of Vout/Vin.

if you connect your OPA as unity gain buffer, Vout/Vin=1
then , you can get PSRR from =PSR/1

 

[PaloAlto]

if you connect your OPA as unity gain buffer, Vout/Vin=1 then , you can get PSRR from =PSR/1

Uuummmm, is your gain going to be 1 for the entire frequency range? ;-)))

You better just use the ratio, that's safer.