Good morning, I am having some trouble with a comparator circuit I've designed on a IO breakout board that I'm hoping I can get some help with. The circuit in question is the front end to a fan circuit. The purpose of the comparator circuit, U199 is to detect whether or not there is a thermistor installed on J37. The reason for this is primarily thermal management. If there is no thermistor installed, the fan circuits for U195, U194, U196, and U197 will not be engaged, because there is no voltage on pin 1 of the FAN IC's. To solve this corner case, I decided to add a inverting comparator, U199 with a isolation switch U200 to prevent the feedback loop from following the output of the comparator. The primary issue I'm having with this circuit, is that when there is no thermistor installed, the -In pin is always about -10mv to -30mV above +in. This is interesting because without a thermistor installed I would expect -In to be 0V due to R1182 acting as a pulldown, and +In to be around 100mv. In this operational case, -In measured to be 125mV with +In measuring at 100mV. I expect the inputs to have an offset, but I did not expect the -In pin to have a DC bias voltage that tracks to the +in pin. Can you explain why this is happening? I've adjusted the resistor divider feeding the +in pin many times to voltages up to 1.5V and this behavior is consistent, which leads me to believe that I've made a design mistake. Can you explain what I have done wrong and how to possibly correct this, if you have any ideas? Schematic is attached for your reference.