Designer’s Guide Community

Pages: 1

Remove the compensation cap, the opamp still stable? (Read 2257 times)

ludake New Member Offline Posts: 1	Remove the compensation cap, the opamp still stable? Jul 05^th, 2016, 4:37pm I built a regular 2-stage opamp with one compensation cap..... when i remove this cap, i see in the ac simulation that the phase margin is not enough, but in the transient simulation, i can't see the opamp is oscillating ? what't happening??? [ [img][/img]
Back to top	image002.jpg IP Logged

buddypoor

Community Fellow

Offline

Posts: 529
Bremen, Germany

Re: Remove the compensation cap, the opamp still stable?
Reply #1 - Jul 6^th, 2016, 12:52am

ludake wrote on Jul 5^th, 2016, 4:37pm:

I built a regular 2-stage opamp with one compensation cap..... when i remove this cap, i see in the ac simulation that the phase margin is not enough, but in the transient simulation, i can't see the opamp is oscillating ?
�what't happening???
[ [img][/img]

Oscillation will occur in case of a closed feedback loop only. Did you apply feedback during TRAN simulations?

LvW (buddypoor: In memory of the great late Buddy Rich)

IP Logged

loose-electron Senior Fellow Offline Best Design Tool = Capable Designers Posts: 1638 San Diego California	Re: Remove the compensation cap, the opamp still stable? Reply #2 - Jul 6^th, 2016, 7:55pm That is not an Op-amp, that is an OTA. That said buddy is right about the feedback
Back to top	Jerry Twomey www.effectiveelectrons.com Read My Electronic Design Column Here Contract IC-PCB-System Design - Analog, Mixed Signal, RF & Medical IP Logged

Pages: 1

‹ Previous topic | Next topic ›