Hello , I have the following amplifier, its not large gain so i cant assume virtual ground.
How do i analize the transfer frunction of such amplifier?
Thanks.

https://www.analog.com/en/products/ad8277.html

 

This tutorial should help.

 

It is not the gain of the closed loop configuration. It is the OPEN LOOP gain of the basic amplifier that allows feedback system to spin their magic.

 

So in my open loop gain is 1 correct?
Thanks.

 

So in my open loop gain is 1 correct?
Thanks.

ABSOLUTELY not!! RTFDS very very cafrefully and take note of Figure 16. which I have reproduced here.


With the stated conditions the open loop gain is 100 dB which corresponds to a GAIN of 100,000. That is a far cry from an open loop gain of 1 which makes absolutely no sense at all. It is true that unity gain in the open loop configuration is achieved at 2 MHz.

Most, if not all opamps have a low frequency pole in the 10's of Hertz range, giving them a large open loop gain at low frequency.