Original question:
OPA4376: OPA4376 - resistance range for thermistor sensing circuit
Hello guys,
One of my customers is going to use OPA4376 for their new products. But they use 3 opamp only and don't use remain 1 opamp.
They want to know how to treat unused input pin of the opamp of OPA4376?
I think a voltage follower circuit configuration with no inverting input connected to GND is general solution.
Is my understanding correct?
Your reply would be appreciated
Kazuya,
Placing an unused amplifier in a follower configuration with the input grounded would be fine in a dual supply application but not in a single supply where output may not swing all the way to ground. For that reason, in a single supply application you need to make sure that the input and output operates within OPA4376 linear range - 50 mV or more from either rail (see AOL conditions). This may be accomplished by driving the input with a resistive voltage divider between the rails. For more, please read the following blog: 
