title: Miniaturizing Ultrasonic System for Portable Health Care and Fitness.
abstract: We present a miniaturized portable ultrasonic imager that uses a custom ASIC and a piezoelectric transducer array to transmit and capture 2-D sonographs. The ASIC, fabricated in 0.18 μm 32 V CMOS process, contains 7 identical channels, each with high-voltage level-shifters, high-voltage DC-DC converters, digital TX beamformer, and RX front-end. The chip is powered by a single 1.8 V supply and generates 5 V and 32 V internally using on-chip charge pumps with an efficiency of 33% to provide 32 V pulses for driving a bulk piezoelectric transducer array. The assembled prototype can operate up to 40 MHz, with beamformer delay resolution of 5 ns, and has a measured sensitivity of 225 nV/Pa , minimum detectable signal of 622 Pa assuming 12 dB SNR ( 4σ larger than the noise level), and data acquisition time of 21.3 ms. The system can image human tissue as deep as 5 cm while consuming less than 16.5 μJ per pulse-echo measurement. The high energy efficiency of the imager can enable a number of consumer applications.
authors.forename: Hao-Yen
authors.initials: HY
authors.lastname: Tang
authors.forename: Dongjin
authors.initials: D
authors.lastname: Seo
authors.forename: Utkarsh
authors.initials: U
authors.lastname: Singhal
authors.forename: Xi
authors.initials: X
authors.lastname: Li
authors.forename: Michel M
authors.initials: MM
authors.lastname: Maharbiz
authors.forename: Elad
authors.initials: E
authors.lastname: Alon
authors.forename: Bernhard E
authors.initials: BE
authors.lastname: Boser
mesh_terms: D004867:Equipment Design; D006801:Humans; D055616:Microtechnology / Q000295:instrumentation*; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation*