I am trying to make a simple Schmitt trigger circuit with the TLV9302. Input voltage is 5V. On the non-inverting input, I have a voltage divider from the 5V supply using two 10k resistors, with a 1M hysteresis resistor. The inverting input has a signal that measures a temperature using a 1k thermistor. The unused op-amp in the dual package is set up as a voltage follower with the non-inverting input connected to GND.

[![Schematic snippet showing a Schmitt trigger circuit - the non-inverting input has a voltage divider from 5V using 10k resistors, the output connects to the non-inverting pin through a 1M resistor for hysteresis, and the inverting input is a voltage divider with the low side connected to a 1k thermistor][1]][1]

According to simulations and calculations, this should give a window of ~25mV centered at 2.5V. However, the midpoint reads ~2.4V. This does not seem like a huge difference, but 100mV will make a difference in my application.

I removed the hysteresis resistor, and just measured the voltage of the divider. The top resistor reads 2.6V, the bottom reads 2.4V. I confirmed the divider resistors are a solid 10k (they are 0.1% components!)

There are no other connections to the node, except the non-inverting input of the op-amp. By my calculations, this means that ~20uA is apparently flowing into the non-inverting input of the op-amp??

As far as I can tell, the board is free of shorts. The op-amp inputs are *not* clamped to each other internally (one reason I chose this part). I'm a bit at a loss of what's going on here. The only thing I can think of at this point (the last bastion of a troubled designer) is the op-amp is damaged somehow; I may try replacing it.

Anyone have any ideas?? Thanks!

Datasheet:
https://www.ti.com/lit/ds/symlink/tlv9302.pdf?ts=1750967442834&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTLV9302


 [1]: https://i.sstatic.net/Ol5UvIr1.png