A 1.54mW/Element 150μm-Pitch-Matched Receiver ASIC with Element-Level SAR/Shared-Single-Slope Hybrid ADCs for Miniature 3D Ultrasound Probes

This paper presents an ultrasound receiver ASIC in 180nm CMOS that enables element-level digitization of echo signals in miniature 3D ultrasound probes. It is the first to integrate an analog front-end and a 10-b Nyquist ADC within the $150 \mu \mathrm{m}$ element pitch of a 5-MHz 2D transducer array. To achieve this, a hybrid SAR/shared-single-slope architecture is proposed in which the ramp generator is shared within each $2 \times 2$ subarray. The ASIC consumes 1.54mW/element and has been successfully demonstrated in an acoustic imaging experiment.