Electronic – Opamp operation with “unbalanced” power supplies


Usually the way to operate an opamp is to feed a +V and a -V of the same magnitude but opposed polarity. Or, just +V and GND.

But now, I need an opamp's output to be In a different range. About -1.25V to +28V. The opamp i have is an MC4558, which has a supply voltage (max) of ±22V.

Can I supply this with, say, -3V and +33V? The configuration I'm using is drawing "B" in this answer: Setting LMC6001 offset voltage

Some opamps, like the LM324, say supply can be 0-36 or ±18V. This one only mentions ±22V. It doesn't say 0-44V.

Best Answer

The opamp itself won't notice any difference in -10/+30V or -20/+20V power rails as the 0V is not connected to the device, only to the surrounding circuitry. It is up to you to define 0V somewhere in your circuit and you can change it at any moment. Just beware that all other node voltages change with that decision.