2C-3 An Integrated Circuit with Transmit Beamforming and Parallel Receive Channels for 3D Ultrasound Imaging: Testing and Characterization

The cost and complexity of medical ultrasound imaging systems can be reduced by integrating the transducer array with an integrated circuit (IC). By incorporating some of the system´s front-end electronics into an IC, bulky cables and costly system electronics can be eliminated. Here we present an IC for 3D intracavital imaging that requires few electrical connections but uses a large fraction of a 16times16-element 2D transducer array to transmit focused ultrasound. To simplify the receive and data acquisition electronics, only the 32 elements along the array diagonals are used as receivers. The IC provides a preamplifier for each receiving element. Each of the 224 transmitting elements is provided an 8-bit shift register, a comparator, and a 25-V pulser. To transmit, a global counter is incremented from 1 to 224; each pulser fires when its stored register value is equal to the global count value. Electrical testing of the fabricated IC shows that it works as designed. The IC was flip-chip bonded to a two-dimensional capacitive micromachined ultrasonic transducer (CMUT) array. A two-dimensional image of a wire target phantom was acquired.