how to simulate the PSRR in transition simulation ?

[twonsr]

hi :

I have a trouble to simulate the PSRR about my voltage regulator.
I want to know my circuit's stability with vdd fluctuation , so I let my vdd to be a sin wave as sin( 10 15m 10k 0 0 0 )
10 is the vdd , 15m is the amlitude and 10k is the frequency.
And then I give a ".TRAN" instruction to get the output's fluctuation.

But I find if I add accurate=1 in options , the result will change very much.
Why ?

If my simuation method is wrong , please help me and give me some suggestion.
Thank you very much.

 

[wee_liang]

You should use ac analysis. Put an ac=1 source on your power supply and run ac analysis, look at the output node performance in freq response.

I'm not sure about the accurate=1 thing.

 

[chinito]

To measure PSRR, you would connect your output back to the input (negative terminal), ground positive terminal and run ac analysis on VDD and plot output.

 

[mists]

maybe you can also try to add a sine source in power supply in tran analysis to see output, but this is only for verification.

 

[raymond33]

The best way to know your PSRR of your circuit is to perfprm AC analysis as wee_liang told you AC=1.
But you need to perform this AC analysis for the both supply (i.e VDD and the ground) ,so two different analysis

 

[cetc1525]

I want to know the PSRR is equal to ripple rejection?