√x circuit based on a novel, back-gate-using multiplier
A simple low-power low-voltage square-rooting circuit (or √x circuit) is presented. This circuit is based on a novel multiplier that uses the back gate of a MOSFET biased in weak inversion. A breadboard implementation has shown an error of less than 20% with respect to the desired transfer over an input current range from 4pA to 80nA.
