A 65nm CMOS Front-end LNA for Medical Ultrasound Imaging with Feedback Employing Noise and Distortion Cancellation

Abstract

A high performance 67.2uW low power front-end Low Noise Amplifier (LNA) for ultrasound applications is proposed. The amplifier utilizes a balun based on a common-gate (CG) and a common-source (CS) combination. The CS-amplifier performs error correction, and thus cancels distortion and noise from the CG-amplifier. The proposed design introduces a GM-boosted CG-amplifier for further linearization and HD2-supression. Furthermore, a programmable-gain scheme has been introduced. The amplifier is tailored towards a capacitive micro machined ultrasonic transducer (CMUT), with an impedance of 10k<-60 at a center of frequency 5MHz.Layout for the amplifier is created, and the LNA is design and simulated under 65nm CMOS including layout effects. Consequently, achieving a noise figure (NF) of only 2.98dB with a total power consumption of only 67.2uW, with an input impedance of 3k8. The final design sports a dynamic range (DR) of 50.35dB. Total harmonic distortion is simulated to -62.43dB with an IM3 of -41.47dB and HD2 of -56.63dB.