Differential Input Voltage OpAmp parameter

[cmb042]

What is the differential input voltage parameter on an opamp mean? Does +/- 10V mean I can have a 20V difference between the two inputs not exceeding +10 or -10. Or that any one input as a reference the other can't go beyond 10V from it? What happens if you exceed this number? Does it snub or chop off the signal outside that range? Or does it just shut down with no ouput?

 

[VEBill]

This one: "can't go beyond 10V from it"

First effect might be non-linearity. Final effect might be smoke. Simple answer is: don't go there.

Stand-by for others input.

 

[cmb042]

Hmm, so no output but no smoke means just a tiny amount of smoke?

 

[zappedagain]

Your output might clip (distortion). You might get phase inversion. Your part might still function after a little bit of smoke if you turn off the power fast and fix the problem, but I wouldn't ship a product to a customer unless ALL the smoke was still inside.

Check out some of the papers from National Semiconductor or Analog Devices for more information on op amp specifications.

Z

 

[cmb042]

Wait a minute, if the opamp is not functioning as a differential amplifier, grounded noninverting and feedback to the inverting, then that parameter shouldn't come into play correct? The output would feedback and drive the voltage on the input down before it could get to the limit.

 

[IRstuff]

Wait a minute, an opamp is ALWAYS functioning as a differential amplifier.

You can readily get conditions where the two inputs diverge, because of transient response effects, etc.

If the inputs are rated +/- 10V, the maximum rating is usually around +/-20, so it shouldn't catastrophically smoke.

TTFN

FAQ731-376