New ISFET sensor interface circuit for biomedical applications

This article presents a novel architecture of an ISFET sensor interface cir cuit, monolithically integrated on a 3D MCM, part of a biomedical microsyst em. It is a differential configuration with two ISFET devices (one with Si3 N4 ion sensitive layer, the other with SiO2 sensitive layer) and realized i n 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 co nfiguration been optimized during a calibration step of the system. (C) 199 9 Elsevier Science S.A. All rights reserved.