A Multichannel Pipeline ADC for an Integrated 3-D Ultrasound Imaging System

An 8-channel, 10-bit pipeline analog-to-digital converter (ADC) designed for use in an integrated 3-dimensional ultrasound imaging system， has been implemented in a 0.25-µm CMOS technology。 Two parallel sample-and-hold stages are employed to multiplex a total of 8 adjacent ultrasound channels， each sampled at 20 MHz. The sampled and multiplexed signals are fed into two parallel pipelines， each operating at 80 MHz. These two pipelines are subsequently multiplexed into a single pipeline operating at 160 MHz to conserve area。 An experimental prototype of the proposed architecture occupies less than 4 mm2 of silicon area and achieves a peak SNDR more than 54 dB for a 2.1-MHz input signal，while dissipating only 20 mW per each analog input channel from a 2.5-V power supply。