Other Parts Discussed in Thread: LM393
Hello expert,
Customer would like to use LM393B to compare -12V voltage. May I know if we need to apply V+=0V and V- = -12V to meet Vcm requirement in datasheet page 6? Thanks a lot!!
Best regards,
Ann Lien
This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
Hi Ann,
yes, this is one method. The GND pin of LM393B should be <= -12V then.
Another method is the potential shifter which uses a pull-up and pushs up the input signal by the help of a voltage divider. A simple example is shown below:
The advantage: The LM393 needs no longer to be powered by a negative supply voltage with the shifter. Of course, you must never violate the absolute maximum ratings referring to the input voltage. So, eventually, an additional protection circuit might be needed:
Kai