Multiple-gate split-drain MOSFET magnetic-field sensing device and amplifier

Abstract

A new split-drain MOSFET magnetic-field sensing device is reported which uses multiple gates to establish a longitudinal electric field in the channel. A relative sensitivity of 185 mA/AT was measured for a double-polysilicon, multiple-gate, split-drain MOSFET. A triple-drain multiple-gate MOSFET device achieved relative sensitivities greater then 10,000 mA/AT. A new amplifier circuit for the multiple-gate, split-drain device achieved an absolute sensitivity of 10 V/T at a 400 nA bias current corresponding to a relative sensitivity of 2.5*10/sup 7/ V/AT. The intrinsic power dissipation of the magnetic amplifier sensor is as small as 8 mu W.<>