Streamline medical ultrasound designs with monolithic Doppler phase-shifter

Norwood, Mass — Analog Devices, Inc. has created an IC that simplifies the development of continuous wave (CW) Doppler imaging in stationary and portable ultrasound systems.

CW Doppler is an advanced Doppler technique that is used in roughly 30 percent of today's cardiac ultrasound equipment. It allows physicians to accurately assess the physical state of arteries, veins and blood vessels by quickly detecting blood flow and direction.

This IC is the industry's first dual-channel I/Q demodulator and phase-shifter for CW Doppler ultrasound, said Jay Cormier, product line director of the Linear Products Group at Analog Devices. "The device achieves a dynamic range of 161 dB per √ Hz, which is equal to or exceeds the dynamic range of existing multichip solutions, while using less than 25 percent of the board space per channel and delivering a per channel BOM savings of up to 75 percent," he added.

Because analog beam forming (ABF) analog front ends typically comprise discrete crosspoint switches or custom ASICs, manufacturers have been forced to accept significant cost and board space penalties, according to Cormier. "The AD8333, by comparison, provides the same coherent summing and phase alignment of multiple input channels as competing products while consuming just 190 mW/channel and significantly reducing circuit board area," he explained.

The phase-shifter is designed with 22.5° phase steps, allowing for accurate time alignment of multiple channels in continuous wave beam forming applications. The amplifier offers parallel 4-bit digital control of phase states, and provides accurate channel matching through a common LO interface. Additional applications include weather radar, adaptive antenna arrays, and automotive collision avoidance systems.

The AD8333 monolithic Doppler phase-shifter is currently sampling and will be in full production in August 2005. The device is offered in a 5mm x 5mm LFCSP and is priced at $8.95 each in 1,000-unit quantities. Click here for the AD8333 data sheet.

Analog Devices, 1-800-262-5643, www.analog.com.