My customer is using LMV931. The schematic is configured as a buffer as below picture. Power supply is single 3.6V.
When we tied pin1 to GND, pin4 output voltage is close to 0V which is normal.
But when we make pin1 floating, we measured that pin1 voltage is ~150mV and Pin4 output is ~2.8V which is abnormal.
Picture1: Test condition: Pin1 is floating. Yellow=power supply=3.6V, Blue=Pin4 output=2.8V,
Picture 2: Test condition: Pin1 is floating. Yellow=power supply=3.6V, Blue=Pin1 =~150mV
So could you please help advise why pin1 has a ~150mV voltage when it is floating? And why the Pin4 output is 2.8V when Pin1 input is floating(Pin1 measured voltage is ~150mV)? I have confirmed with customer that there's no additional RC component on Pin1 when it is floating. Thanks.