Low-power current-mode logarithmic pipeline analog-to-digital converter for ISFET based pH sensor

This paper describes the design and realization of a low power current-mode logarithmic pipeline analog-to-digital converter in 0.35 mum CMOS technology. The ADC is intended for conversion of sub-microampere analog output current of an ISFET based pH sensor. Subthreshold MOSFETs and the translinear principle are exploited to achieve simple and low-power ADC realization. The ADC was simulated with a 1-V power supply voltage and dissipated 3.3 muW static power at 1-kHz clock frequency.