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I have an opamp and would like to keep it in class A output. The rule of thumb is 1/2 of quiescent current should not be taken by the load. (to keep it in class A)

The load itself is a R feedback (inverting feedback) going to opamp negative and then a R going to ground

Since I know that no current can flow into opamp inputs (or rather very small) should I calculate this R (feedback) into total load ?

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  • \$\begingroup\$ I think that opamps don’t normally ever work in class A. \$\endgroup\$
    – Andy aka
    Commented Jan 23, 2020 at 16:30

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The simple answer is yes. You need to take into account the current used by the feedback resistors as well as that required by the load. Amps with class A output stages are rare to non-existent today, but they were made in the ( now ) distant past. (@Andy aka : I have two such ICs in my collection of old devices.)

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