phase margin and gain margin op amp

Status
Not open for further replies.
B

biolycans

Member level 2
Joined
Aug 24, 2013
Messages
50
Helped
0
Reputation
0
Reaction score
0
Trophy points
6
Visit site
Activity points
478
Hi,

I designed an operational amplifier two stages cmos and what I want to do is to verify the phase margin and gain margin of this circuit. What configurations should I use for this circuit ?

Regards

Joaquin
 

PM and GM are important in a closed loop ckt like a buffer. In open loop configuration the 2stage op-amp is more like a comparator.
So you can use any closed loop configuration, simplest being an unity gain buffer. Then just do a stability analysis and find the PM & GM and compensate accordingly.
 

SIDDHARTHA HAZRA said:
So you can use any closed loop configuration, simplest being an unity gain buffer. Then just do a stability analysis and find the PM & GM and compensate accordingly.
Click to expand...

Just to avoid misunderstandings:
Unty gain applications with 100% feedback are the most critical configuration as far as the stabilty is concerned.
However, determination of stability margins is done using open-loop configuration (loop gain).
For unity-gain feedback this is identical to measure/simulate the opamps open-loop gain (magnitude and phase).
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…