Hello dear forum,
after a bit longer break I'm sitting again on my circuit with a MEMS microphone at the input, but this time it's an analog one ;)
The following topic:
I have built a circuit that I'm still testing, but I'm working on auto-zero drift OPV's on the side.
I have installed the AD8638 as a spice model in LTSpice, but how do I get it to work, that it brings my DC signal down to 0V at the output, how does that work?
I use a micro from TDK InvenSense 40619 and an AD797 OP as a differential amplifier for it.
I had a compensation circuit built into LTSpice, but it makes the circuit unbalanced. Likewise, I have lower gain in LTSpice by imaging the mic with two analog voltage sources, one normal signal and one inverted (180° out of phase).
Where does this come from?
I wanted to have, with a difference voltage of 2V (max) at the output a voltage of about 8V, now it is only a gain of about 1-2...as I said, I will test the circuit next week.
Oh yes and coupling capacitors I do not want to take because of the time delay.
Also, someone said I should switch to an instrumentation amplifier, like the SSM2019.
There would of course be the same question because of the auto-zero drift OP.
I hope someone here can help me...
Best regards
Edit Notes
Additional Info written (SSM2019)[edited by: Ovid at 3:14 PM (GMT -4) on 3 Jun 2023]
