Pipelined delay-sum architecture based on bucket-brigade devices for on-chip ultrasound beamforming

A pipelined delay-sum architecture based on bucket-brigade devices is proposed as an analog beamformer for integrated far-field steering scanning of a micromachined piezoelectric ultrasonic sensor phased array. The prototype beamformer, fabricated with an 8-μm standard CMOS process, exhibits a total harmonic distortion of -45 dB, dynamic range of more than 65 dB, and beamforming imperfection of less than -50 dB using a 100-kHz input signal with peak voltage of 400 mV.