Hello
I'm trying to pick an Opamp to implement a buffer circuit. I was running simulations to see how the output of the Opamp would change with input. My input will be a square with variable distortion ie the edge time and amplitude are bound to change while keeping the pulse width constant.
So the crucial parameters for me are the Slew rate, bandwidth, and supply voltage. I gave a 1V amplitude square wave with 1us edge time as input. So that's a slew rate of 1 which is well within the limits of the opamp LM7322 (18V/usec). I didn't expect any surprises as the output voltage should just follow the input voltage. But to my surprise, I see a voltage offset of 1V in the output. I checked the opamp parameters and see that I gave an input offset voltage of 0.3V.
I also see the same offset when I tried 15V input amplitude with 1u edge time. The output does follow the input but this offset is something that I dint expect.
So it has unity gain and has an input offset voltage of 0.3V which should give me an offset of 0.3V in the output right? where is this 1V offset coming from?
When I changed the input offset voltage to 2V, I get a 2V offset in the output as expected. This case doesn't hold true when the input offset voltage is below 1V. It's like the minimum offset in the output is 1V. Why is this the case? Any explanation?
Thank you
Varun R
