OpAmp Question

Thread Starter

joemmech

Joined Jan 22, 2010
32
Hi Guys, I have a question about OpAmps. What is the maximum voltage that can be supplied in the non-inverting and inverting input of an OpAmp? Is it ok if the supplied voltage in the inverting input and non-inverting input exceeds the Supply Voltage of the OpAmp? We are using the UA741 OpAmp and there is a note in the datasheet that says "The magnitude of the input voltage must never exceed the magnitude of the supply voltage or 15 V, whichever is less.", what does it mean? Do OpAmps have protection diodes/ ESD diodes inside?
 

mik3

Joined Feb 4, 2008
4,843
Hi Guys, I have a question about OpAmps. What is the maximum voltage that can be supplied in the non-inverting and inverting input of an OpAmp? Is it ok if the supplied voltage in the inverting input and non-inverting input exceeds the Supply Voltage of the OpAmp? We are using the UA741 OpAmp and there is a note in the datasheet that says "The magnitude of the input voltage must never exceed the magnitude of the supply voltage or 15 V, whichever is less.", what does it mean? Do OpAmps have protection diodes/ ESD diodes inside?
Each op amp has different circuitry inside. If the datasheet says you have not to exceed the supply voltage then you have not.
 

russ_hensel

Joined Jan 11, 2009
825
The spec sheet is right. On various op amps a variety of different bad ( unexpected ) things can happen. Reduce the input voltage, voltage divider or some sort of clipping circuit is the way to go.
 

Thread Starter

joemmech

Joined Jan 22, 2010
32
How about protection diode, does the UA741 have a protection diode from Vcc+ and Vcc- going to the non-inverting and inverting input? We look at the specs in the datasheet but we cannot find any data that shows it has a protection diode.
 

beenthere

Joined Apr 20, 2004
15,819
No, that is something a designer might add. It is not very difficult to make a circuit in which an input never exceeds a particular level.
 
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