Hello all and thank you in advance for taking a look at my problem.
I have made a circuit which takes a differential voltage from a Wheatstone bridge (pressure transducer) and converts to an analog voltage to be read by an ADC.
The first stage of the amplifier takes the differential input and outputs at unity gain. Pin1 of IC4G1 is outputting ~.2 volts with no pressure applied to the transducer. I think the output of the first stage should equal the voltage measured across the output of the transducer.
On the pressure transducer, IC2, the voltage Vpin4-Vpin2 = -5mV. After cutting the traces going to the op amp, that same measurement yields 0V (as I would expect with zero pressure on the transducer.)
The second stage of the op amp should have a 100x gain but behaves like it has around 50x gain.
Here is a screenshot of our layout.
Hopefully there is something simple we're missing.
If there is any information I've missed let me know and I'll get it posted ASAP. We're in a bit of a crunch to get this solved.