Ultra Low-Power Low-Voltage Integrated Preamplifier Using Class-AB Op-Amp for Biomedical Sensor Application

An ultra low-power low-voltage (LPLV) integrated preamplifier using class AB op-amp for biomedical sensor application is presented in this paper. This paper includes the design of an ultra LPLV class AB op-amp, current references, and half-VDD references in weak inversion region. Total power consumption of these three blocks is approximated 3 muA for IV supply. Measured power supply rejection ratio (PSRR), slew rate (SR) and input offset of the op-amp are 50 dB, 10 mV/muS and <2 mV respectively. Due to the fact that folded cascade class AB op-amp is used in this design, the preamplifier has wide input common mode range (ICMR), which is 0.75 V for IV supply, and rail-to-rail output with high driving capability which is highly demanded in biomedical sensor application. The design has been implemented in 0.18 mum CMOS technology.