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

In this paper we present the measurement results of a 1 V transimpedance amplifier designed in a 90 nm 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 15 MHz to 45 MHz with a center frequency of 30 MHz. The measurements show that the proposed amplifier achieves a voltage gain of 15.5 dB, an output noise power spectral density of 0.0497 (¿V)/SQRT(Hz) at a center-frequency of 30 MHz, and a total harmonic distortion of -28.8 dB, at 400 mV p-p output voltage at 30 MHz input signal frequency. It draws only 450 ¿A 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 ¿m × 26 ¿m only per amplifier.