Shunt-Zero Based on CMOS Split-Drain: A Practical Approach for Current Sensing

A current sensor circuit intended for integrated smart-power applications featuring galvanic isolation is devised. It is based on magnetic detection using the CMOS compatible split-drain transistors (MAGFET) that provides linear output current versus magnetic field from DC to several MHz range. An integrated sensor built in 0.35 mum CMOS technology presented an output conversion factor of 500 nA/A, corner frequency around 1 MHz and thermal spectral density of 60 pA/radicHz for a power dissipation of less than 15 mW