Hello,

I am just wondering if anyone knows of any issues with running an op amp constantly at its supply voltage. Is that in any way damaging to the op-amp? Im thinking about a comparator that is running with a dc input voltage on one of its pins that forces it to run at its positive supply voltage entirely. Is this damaging to the op-amp?

Thanks,

Dtow1

 

As long as the supply voltage is within the device's ratings and you are not drawing excessive current from the output, it will not be a problem.

 

i have to disagree - but only because that usually is in violation of the op-amps characteristics.

generally speaking all op-amps require some headroom on the rail voltages when compared to the input voltage.

even if you had a +12V supply rail and applied a +12V signal the signal would only reach within a certain amount of the rail (typically on the order of 1-2V)

 

Thank you very much, that is very helpful.

 

It would be most helpful if you would post your circuit.

Some opamps have rail-to-rail inputs, and some also have rail-to-rail outputs.

As kingdano implied, many older opamps and comparators cannot "see" inputs that are within a few volts of the positive supply rail. Some can't see inputs that are within a couple volts of the negative supply rail.

You can use resistors and/or pots as voltage dividers to keep your input within the range of the opamp or comparator in question.

 

sgt wookie is correct - but without an op amp model or circuit i steered towards general op-amp behavior.


thanks for clarifying sgt.