A Reduced-Wire ICE Catheter ASIC With Tx Beamforming and Rx Time-Division Multiplexing

This paper presents a single chip reduced-wire active catheter application-specific integrated circuit (ASIC), equipped with programmable transmit (Tx) beamforming and receive (Rx) time-division multiplexing (TDM). The proposed front-end ASIC is designed for driving a 64-channel 1D transducer array in intracardiac echocardiography (ICE) ultrasound catheters. The ASIC is implemented in 60 V 0.18-μm HV-BCD technology, integrating Tx beamformers with high voltage (HV) pulsers and Rx front-end in the same chip, which occupies 2.6×11 mm 2 that can fit in the catheter size of 9 F (<3 mm). The proposed system reduces the number of wires from >64 to only 22 by integrating Tx beamformer which is programmable using a single low-voltage differential signaling (LVDS) data line. In Rx mode, the system uses 8:1 TDM with direct digital demultiplexing (DDD) providing raw channel data which enables dynamic Rx beamforming using individual array elements. This system has been successfully used for B-mode imaging on standard ultrasound phantom with 401 mW of average power consumption. The ASIC has a compact element pitch-matched layout, which is also compatible with capacitive micromachined ultrasound transducer (CMUT)-on-CMOS application. This system addresses cable number and dimensional restrictions in catheters to enable ICE imaging under magnetic resonance imaging (MRI) by reducing radio frequency (RF) induced heating.