Hello,
I am constructing a transimpedance amp for a Ion Chamber using the LMP7721 op-amp. I have simulated the design using TINA-TI software with successful outcomes. I am having a few problems building my design and have it functioning currently. The attached .zip TINA file is the design and I also didn't include the guard circuit in my construction.
The problems I face are the following. There is some negative voltage feedback being applied to the inverting input to the Ion Chamber that I can't explain. No matter what the inputs values are the output will swing to the positive rail even when shorted together to ground.
Any input on these problems will be greatly appreciated.
Thanks,
Lee