A 201 mV/pH, 375 fps and 512×576 CMOS ISFET sensor in 65nm CMOS technology

This paper presents a high-gain and large-scale CMOS ion-sensitive field effect transistor (ISFET) sensor. The high-gain readout is achieved by a novel pH-to-Time-to-Voltage conversion (pH-TVC), which can greatly increase pixel density (small pixel size) with a high sensitivity. The proposed pH sensor consists of 512×576 pixel array with 3.9um×3.9um chemical sensing area, and is integrated with column-paralleled 10-bit single-slope ADCs to speed up data readout. It is fabricated in traditional TSMC 65nm process with 201mV/pH sensitivity and 375 fps readout speed, targeted for DNA sequencing.