power supply noise in HSPICE

[an_82]

I want to test an analog circuit against power supply noise in HSPICE. How can I apply noise signal to VDD? (Which command, or example)

 

[erikl]

You'd probably want the PSRR over frequency? Add a unit ac source to your power supply (either to VDD or to GND) and run an ac (or an xf) analysis. The ac voltage at the output represents the PSRR.

 

[crutschow]

To clarify erikl's suggestion, the AC Source must be added in series with the power supply voltage source.