A beam-forming transmit ASIC for driving ultrasonic arrays

This paper describes the design of a programmable eight-channel application specific integrated circuit (ASIC) for driving ultrasonic array transducers. The ASIC is capable of generating variable delay lengths of up to 65 μs in steps of 1 ns. Integrated on the same chip is an array of eight high-voltage pulser circuits (up to 100 V). The output pulse width can also be set to match the transducer operating frequency. A minimum width of 20 ns is possible and the rise and fall times are typically 5 and 7 ns. It can also be programmed to give bursts of up to 16 repetitions to facilitate Doppler imaging.