1V transimpedance amplifier in 90nm CMOS for medical ultrasound imaging

In this paper we present the measurement results of a 1V transimpedance amplifier designed in a 90nm CMOS technology as an analog front-end for Capacitive Micro machined Ultrasound Transducers (CMUTs) for medical ultrasound imaging. The proposed amplifier is designed to amplify the signals from 15MHz to 45MHz with a center frequency of 30MHz. The measurements show that the proposed amplifier achieves a voltage gain of 15.5 dB, an output noise power spectral density of 0.0497 (µV)/SQRT(Hz) at a center-frequency of 30 MHz, and a total harmonic distortion of −28.8 dB, at 400mV p-p output voltage at 30 MHz input signal frequency. It draws only 450 µA current from a 1-V power supply. The proposed transimpedance amplifier was fabricated in a 90-nm CMOS technology as it is intended for intravenous medical ultrasound imaging, which demands smaller area for the front-end amplifiers. Area measured to be about 26 µm × 26 µm only per amplifier.