The result is 0.0006% THD + noise performance (Fig. 2b). The 50-MHz OPA365 charge pump boosts the positive supply by about 2 V to supply the input tail current of a pMOS differential pair.

If the PMOS and NMOS transistors are sized so that g m1 = g mb2, the V sub term vanishes and I x = V x (gm1 + gmb1). In this case, the active load impedance ZLOAD = 1/ (gm1 + gmb1) and doesn’t ...