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Dear TI team:
Please help to check LM2901 output level, the VCC is 5V, the test data:
1: IN+ = 4.31V IN- =3.85V OUT=H
2: IN+ = 4.31V IN- =4.35V OUT=L
And I check the information from datasheet as below, I think the 3.85V/4.31V/4.35V are>3V, so it would be output L, but it output H when "IN+ = 4.31V IN- =3.85V "
Thanks!
Regards!
Eric
Hi Eric,
As Kai siad, you are operating outside the specified input voltage range. At 4.3V, you are in the "teetering-over-the-edge-about-to-die" range. Hit it with cold spray and see what happens...
See the following Appnote, section 2.2:
Application Design Guidelines for LM339/LM393/TL331 Family Comparators
It will *seem* to work now, but you will eventually get failures.
I was never fully on-board with the last bullet point that you highlighted. There could be bias points where there is *juuust* enough leakages to push the output in one direction or the other - and it may not be in the direction you want. I think you found one of those points....
Please re-adjust your input voltages so they fall <3V, or increase the comparator supply voltage to >6.5V to ensure proper operation. If you cannot change the input voltages, replace the LM2901 with a TLV1704 or similar rail to rail input device.