High-Sensitivity Regulated Inverter Cascode Transimpedance Amplifier for Near Infrared Spectroscopy

This paper presents a design and a post layout simulation of a high-sensitivity low-power transimpedance amplifier (TIA) for frequency domain near infrared spectroscopy (FD-NIRS). The TIA consumes 340 mu W from a 1.2 V DC supply. This low power is necessary for NIRS device portability. The proposed TIA achieves 104.8 dB Omega transimpedance gain, 50 MHz bandwidth and 15.1 nA(rms) total integrated input noise current for 2 pF off chip photodiode capacitance. The demonstrated TIA is simulated using 130 nm CMOS technology and occupies an area of 0.0012 mm(2). Post amplifier stage is presented to increase the total gain. The complete NIRS optical receiver achieves 119.5 dB Omega gain, 49.2 MHz bandwidth, 15.4 nA(rms) total integrated input noise current and consumes 400 mu W from a 1.2 V DC supply.