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Op amp input overvoltage protection

Question asked by rehfi on Sep 23, 2015
Latest reply on Oct 2, 2015 by rehfi




I'm busy with op amp input overvoltage protection. I'm aware of MT-036 and the ADA4177 or ADA409x op amp families. Limited space won't allow me to add external parts like diodes, but the op amps with internal protected are quite slow and I need more speed.



The op amp datasheets usually contain a sentence like "If the inputs are expected to be subject to overvoltage conditions, insert a resistor in series with each input to limit the input current to ±10 mA maximum"



My question is:

When I add the current limiting resistor, does the above sentence allow me to violate the usual Vneg-0,3/Vpos+0,3 absolute maximum rating? Does it allow me to do this permanently?  I'm aware that the functional operation will not be given under these circumstances.