I am trying to monitor a negative voltage as per the application diagram in datasheet page number: 8, Figure:6. The other three sense inputs are given 2.5V.
Value of R1 used is 11K and R2 is 8.25K. When i provide a proper negative voltage, functioning is OK. IC is powered from a +15V supply and threshold is selected to be +/-10% by giving 1V to Window adjust pin..
However, when i leave the input line floating (totally unconnected), the output is still showing "HEALTHY" (POWER OK=HIGH/Floating) STATUS whereas i was expecting a "FAULT" (POWER OK = 0V/LOW) since
1. there is a feedback resistor of 11K and
2. pin 3 is grounded
pin 5 also will be virtual ground and pin 6 will also be close to zero (anyway beyond +/-10% of 2.5V).
Am i making any connection mistake, or is this the expected output from the IC?
The problem goes away if
1. i provide a high value (mega ohms) pull down resistor from pin 5 to ground.
2. i connect a high value (mega ohms) resistor from -Vs to ground.
Can someone help me with this issue?
