A 1.2 mW/channel 100µm-Pitch-Matched Transceiver ASIC with Boxcar-Integration-Based RX Micro-Beamformer for High-Resolution 3D Ultrasound Imaging

The integration of 2D ultrasonic transducer arrays and pitch-matched ASICs has enabled the realization of various 3D ultrasound imaging devices in recent years [1]–[3]. As applications such as 3D intravascular ultrasonography, intra-cardiac echocardiography, and trans-fontanelle ultrasonography call for miniaturization and improved spatial resolution, higher-frequency transducers (>5MHz) with a correspondingly smaller array pitch (<150µm) are needed. Such devices generally employ a large number of transducer elements, calling for channel-count reduction in the ASIC while meeting stringent restrictions on per-element power consumption and die area. Micro-beamforming (µBF) is an effective way of reducing channel count by performing a delay-and-sum operation on the echo signals received within a sub-array [1]. However, prior µBF implementations employ per-element capacitive memory to realize the delay [1], [2], making it increasingly difficult to apply µBF in smaller-pitch arrays.