CMUT-in-CMOS 2D arrays with advanced multiplexing and time-gain control

Technology for producing practical and affordable 2D ultrasound arrays is crucial for expanding the clinical deployment of 3D/4D ultrasound imaging. In addition, low-cost planar arrays may enable revolutionary health monitoring devices that employ 3D data for real-time quantitative measurements of parameters such as such as blood volume flow or tissue motion. CMUT-in-CMOS technology allows high-volume production of ultrasound arrays using a standard integrated-circuit foundry, driving down cost and enabling integration of readout circuits directly on the transducer substrate. The 960-element 5 MHz 2D array reported here demonstrates the advanced capabilities of this approach by integrating capacitive micromachined ultrasonic transducers (CMUTs) with per-element low-noise amplifiers, digitally-controlled time-gain control, and IQ-sampled analog multiplexing to output all signals in real-time while reducing the output lead-count by over 90%. The on-chip circuits come with no added cost or size, showing the benefit of CMUT-in-CMOS for affordable dense 2D arrays, especially for applications that demand high-speed output from many elements.