measure of phase margin command file in hspice

[mike_bihan]

hspice phase margin

I was using command to measure phase margin in hspice.

.meas ac ugain_freq when Vdb(out)=0
.meas ac phase_margin ******* from=1 to=****


The question is how to find the minimum phase from 1Hz to unite-gain frequence?
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[maxwellequ]

hspice .meas ac .measure ac gain

You can try

.measure ac min_phase MIN vp(out) from=1 to=ugain_freq


The phase_margin is, then, min_phase-(-180):

.measure ac phase_margin = param ('180+min_phase')


regards

 

[mike_bihan]

phase margin hspice

fail

 

[maxwellequ]

.measure ac hspice

What happens ? It fails on both measurements (min_phase and phase_margin)?

I've already used this type of measurements several times. You should check the lis file to see if there is any relevant warning.

 

[mike_bihan]

phase margin measurement spice

the reason i failed is that I typed ugain_freq as ugain-freq,

so when it is being refered in other .meas commands, it is misinterpreted as 'ugain'-'freq'.

Thanks, it is ok now.

 

[bharatsmile2007]

hspice command to measure phase margin

Hi,

For finding out the phase margin u connect a ACM(ac magnitude) of 1v to inverting or non-inverting terminal.

Thanks

 

[gabicod]

Re: hspice command to measure phase margin

Hi,

For finding out the phase margin
.measure ac phaseM find vp(out) when v(out)=1

Regards