Design Tradeoffs in low-power low-voltage transconductors in weak inversion

Many electronic devices benefit from low-power and low-voltage circuits, increasing their battery lifetime and reducing the physical size of the battery. One such circuit is the transconductance amplifier, the building block of gm-C filters. Tradeoffs in designing a low transconductance transconductor using FETs biased in weak inversion are considered Design equations are presented providing accurate approximations to total harmonic distortion (THD), minimum voltage supply, bandwidth and effects of mismatch. The results obtained with these equations are compared with simulations using the BSIM3v3 model.