Analog Devices Advances Ultrasound System Design With Low-Power Receiver ICs

The new AD9278 and AD9279 receiver chips each integrate ADI’s world-leading data conversion technology for low noise TGC (time-gain-control) mode performance while providing high dynamic range I/Q demodulators that reduce the power and area for implementation of CW (continuous wave) Doppler processing. The new octal ultrasound receivers provide the highest available output-referred large-signal SNR--up to 67 dB--enabling improved sensitivity in diagnostic ultrasound systems while reducing board space up to 40 percent.



“Ultrasound equipment designers must continually balance new and changing demands for higher image quality and increased power efficiency,” said Patrick O’Doherty, vice president for the Healthcare Group, Analog Devices. “The new AD9278 and AD9279 octal ultrasound receivers help system designers manage the design challenges inherent in trying to get the best image quality at the lowest power for either high-end or portable systems.”



The AD9278 octal ultrasound receiver is designed for portable ultrasound systems while the AD9279 octal ultrasound receiver is suitable for high-end and mid-range systems. The devices are pin- and package-compatible with each other and allow designers to use a common PCB (printed circuit board) layout that can be leveraged across multiple ultrasound platforms to save development time and cost.



Products in Analog Devices’ octal ultrasound receiver portfolio include the AD9271, which, when unveiled in April 2007, was the first device to integrate a complete octal ultrasound receiver on a single chip, and is used today in ultrasound equipment throughout the world. Other octal ultrasound receivers include the AD9272 for high-and mid-range cart-based ultrasound equipment, AD9273 for portable ultrasound systems, and the AD9276 and AD9277 that enable high-quality CW (continuous wave) Doppler processing.



AD9278 and AD9279 Octal Ultrasound Receivers Key Features and Benefits



The new AD9278 and AD9279 octal ultrasound receivers feature a variable gain range of 45 dB, a fully differential signal path, an active input preamplifier termination, a maximum gain of up to 52 dB, and an ADC (analogue-to-digital converter) with a conversion rate of up to 80 MSPS. Each device is optimised for dynamic performance and low-power operation in applications where a small package size is critical. In CW mode, the AD9278 features ultra-low power consumption of 25 mW per channel, while the AD9279 offers low power consumption of 50 mW per channel. In TGC mode, the AD9278 consumes only 88 mW per channel at 40 MSPS, and the AD9279 consumes only 139 mW per channel at 40 MSPS. For high-end systems, the AD9279 offers a highly configurable LNA featuring low input-referred noise density of 0.67 nV/√Hz. Download the AD9278 or AD9279 data sheet.



Additional features and benefits include:



* Eight channels offering full TGC path, ADC, and I/Q demodulator contained within a 144-ball, 10-mm × 10-mm BGA (ball grid array) package

* Integrated high dynamic range I/Q demodulator with programmable phase rotation

* A data clock output that operates up to 480 MHz and supports double data rate operation

* SPI (serial port interface) control offering a wide range of flexible features to enable specific power, noise, distortion, and gain optimisation needed for all imagining modes

* Integrated second-order anti-aliasing filter placed before the ADC and programmable from 8 MHz to 18 MHz

* Fast, repeatable overload recovery



Recommended Complementary Components



Complementary components for the AD9278 and AD9279 octal ultrasound receivers include ADI’s AD8021 low-noise, high-speed amplifier; ADA4841-2 low-power distortion amplifier; AD7982 18-bit, 1 MSPS PulSAR® ADC; ADR433 3.0-V ultra-low-noise voltage reference; AD9516 clock generator; AD9520 clock generator; and ADCLK946 and ADCLK846 clock fanout buffers.