Originally Published MPMN June 2008

BREAKTHROUGHS

Chips Enhance Ultrasound Image, Reduce Power Consumption

Stephanie Steward

Understanding the medical industry’s need to make electronics smaller and more products portable, Texas Instruments (TI) has designed a family of fully integrated analog front-ends (AFEs) specifically for portable and high-end ultrasound diagnostic equipment. The AFE58xx chips are engineered to provide enhanced image quality and reduced power consumption compared with existing chips.

“This product has been created in response to an industry need,” says Karthik Vasanth, project line manager, medical business unit. “It looks as though the whole industry is [asking], ‘Can you maintain performance but make your semiconductor chip smaller?’ This chip is our response to that trend,” he says. Vasanth adds that power requirements are a key concern for portable systems, which require long-lasting batteries. Adding more channels without increasing a part’s size is the concern for larger ultrasound systems. The AFE chips have been engineered to address both of these needs.

The first chip in the family, AFE5805, consists of fewer components than previous generations of semiconductors. By reducing the number of components, TI was able to decrease power consumption by up to 20% with a power efficiency of 122 mW per channel. The chip also features low noise levels—40% less noise than similar chips on the market, according to the company—measuring 0.85 nV/rtHz at 2 MHz. This performance level is suitable for portable equipment as well as mid-range and high-channel-density ultrasound systems.

Measuring only 15 × 9 mm, AFE5805 is the smallest AFE currently on the market and is about half the size of existing solutions, according to TI. The chip incorporates eight channels of a low-noise amplifier (LNA), a voltage-controlled attenuator, a programmable gain amplifier, and a low-pass filter. It also features a 12-bit, 50-MSPS analog-to-digital converter with low-voltage differential signaling data outputs.

The low-input-voltage noise level of the on-chip LNA is key to the quality of the complete input signal path, determining the entire system’s performance, including its high resolution. Engineering low noise levels and low power consumption into the AFEs enables OEMs to pack more channels into the same amount of space, which could thereby increase the number of patients screened in an MRI machine, for example.

“If you can see three patients an hour, you can increase that to six because you have the channel power,” Vasanth says. “The same kind of [design] economics is driving miniaturization and lower power in other modalities even though they are not portable.”

Texas Instruments, Dallas
www.ti.com

Copyright ©2008 Medical Product Manufacturing News