A Single-Stage 35dB-Linear Digitally-Controlled Variable Gain Amplifier for Ultrasound Analog Front End

Abstract

This research presents a variable gain amplifier(VGA) for an analog front-end(AFE) of ultrasound imaging machine. The VGA receives an echo signal from LNA, and amplifies the received echo signal for time-gain compensation. The proposed VGA controls 35dB voltage gain in a single stage, and has a large output swing. The proposed VGA has been designed by using a 0.35um CMOS process. The VGA consumes 1.71mW with 3.3V supply. In the post-layout simulation, HD3 of -66.84 dB is achieved for the output voltage swing of 0.9 Vpp. The linear-in-dB gain range is [-17, 18] dB with 16steps. The maximum gain error and the bandwidth of VGA are 1.67dB and 11MHz, respectively.