TLV7031-Q1: In+ & In- pin leakage current

See figure 6-13:

What is the diode? What values do you measure?

the diode is used to limit the voltage at In- pin to 7V 

What are the resistor values? How much variation are you seeing?

Can you provide a detailed schematic (with values and actual part#'s) and the measured voltage values at the temperature points?

TLV7031QDCKRQ1---TLV part no

with 32V Input & Zener diode we expect IN- voltage 5.6884V to 6.323V but we are getting around 6.399V @ HT

with 32V Input & without Zener diode we expect IN- voltage 7.077V to 7.528V but we are getting around 6.623V @HT 

Hi Sharathkumar,

sharathkumar Jidigam said:

with 32V Input & Zener diode we expect IN- voltage 5.6884V to 6.323V but we are getting around 6.399V @ HT

with 32V Input & without Zener diode we expect IN- voltage 7.077V to 7.528V but we are getting around 6.623V @HT 

Are the HT values from measurements or simulation? If it's from measurement, how are you measuring it (multimeter in series?). What are your calculations to get those ranges?

In terms of simulation, you can't use the simulation model to determine specifications over temperature. The simulation model only models typical specifications. The input bias current for the model is a typical -2pA flowing out of the IN- terminal. This current is constant across all temperatures and voltages for the model. The difference in the IN- voltage would be due to the temperature coefficients of your passives (resistors and diode).

The values are from calculations considering the tolerances of the passives including temperature variations , the bias current is very less but other than this any other leakage currents are there in TLV comparator.

one observation without TVS diode the voltage is at the pin is 6.623V but as per calculation it should be max 7.528V, why is it like this because if the external TVS is not there it is a simple voltage divider but any internal voltage limits are avalible?

Hi Sharathkumar,

As far as I know, there are no other leakage currents going into the input pins of the comparator model. Looking at the model, there is only a 2pA typ current flowing into the pin(s). Could you check what voltages you get when you remove the comparator completely (leave only the resistors/TVS diode)? Is that value close to what you get with the comparator connected?

we are planning to like this testing, once will get will update