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Old 16th January 2020
  #16
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Quote:
Originally Posted by Brian M. Boykin View Post
For those still following, what spec in the op amps specs dictates how much gain an op amp can give before it clips? As in, the example in the article is for a 30dB gain increase. What limits a 40dB or 50dB gain in the op amps design?
Clipping or saturation is not a function of gain but output voltage (or current).

Running out of gain, like occurs if the closed loop gain (feedback network) is asking for more gain, than the available open loop gain the gain stage can provide. When that occurs the result is a more graceful tapering off of delivered gain. Since most op amps use dominant pole internal compensation their open loop gain rolls off at very high frequency to prevent instability.

If a designer ignores the inadequate gain and asks for more gain than the op amp can deliver, the result will look like a low pass filter as the circuit delivers less output at high frequency.

This is a simplified explanation but close enough for the WWW.

JR