New ISFET sensor interface circuit for biomedical applications

This article presents a novel architecture of an ISFET sensor interface circuit, monolithically integrated on a 3D MCM, part of a biomedical microsystem. It is a differential configuration with two ISFET devices (one with Si3N4 ion sensitive layer, the other with SiO2 sensitive layer) and realized in a 2.5 mu m CMOS technology. The sensor interface is simple, has a current output signal and low silicon area requirements. The circuit architecture provides digital facilities, which makes possible the performance of the configuration been optimized during a calibration step of the system. (C) 1999 Elsevier Science S.A. All rights reserved.