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I have a low frequency <10Khz sin wave from +12V to -12V and would like to generate a square wave to interface to 3.3V logic. I am looking into the LM211 comparator. I plan to use a +15/-15 supply voltage and a pull up resistor to 3.3V on the output. The inverting input will be tied to analog ground and the input sine wave is at the non-inverting input. the output will be tied to digital ground. Will there be an issue with using two different grounds at the input and output? They are isolated grounds?
This can be tricky to answer without looking at the layout, but when the comparator is low the majority of the current through the pull up resistor will be from the 3.3V supply. The current will return back to this supply, so it will be critical to provide a low impedance path. I presume the 3.3V supply is on the “digital” side of the board.
Answered by: ON Semiconductor
2013-04-08 13:01:12.182