gm limit?

Discussion in 'General Electronics Chat' started by tdlemon, Apr 17, 2011.

  1. tdlemon

    Thread Starter New Member

    Apr 17, 2011
    Hi, I wonder about gm limitation in op amp.
    The input stage of op amp's gm will be root(2beta Id).
    In here, Id is fixed by tail current sink.
    If I increase the input transistor's size, gm also will be increased.
    But where is the gm limitation and why?
    gm was not increased from some value in spite of size increasing.