TPS3803-Q1: SENSE input

Ross,

The SENSE input is very sensitive to injected current. The SENSE input goes to the input of an internal comparator that sinks only 25nA max from the SENSE pin. This means that any injected current even in the nanoamp range, will decrease the trigger voltage. If enough current is injected, the device will think the SENSE voltage is above the internal reference and the output will be logic high even in undervoltage conditions.

There is a technique that utilizes this fact to add additional hysteresis by connecting a single resistor from the RESET output to the SENSE input to add additional hysteresis between VIT+ and VIT- and other than this, I don't know of any reason why current would be injected into the sense pin unless to alter the trigger threshold which can be done by simply changing the sense resistor values.

I hope this answers your question. Let me know if you have additional questions. Thanks!

-Michael