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Scrappy IC Startup Challenges Big Guns With Lossy-Compression ADC For Ultrasound

I recently wrote about Analog Devices’ second-generation analog front ends (AFEs) for medical ultrasound equipment (“Ultrasound AFEs Get More Specialized, Easier To Design With,” ED Online 19819). Meanwhile, Texas Instruments has updated its competing line of ultrasound front-end ICs. TI’s 16-channel AFE5851 and eight-channel AFE5801 target the kind of ultrasound gear that can fit in a doctor’s pocket.

The AFE5851 integrates 16 variable gain amplifiers (VGAs) and eight 12-bit, 65-Msamples/s analog-to-digital converters (ADCs). Each ADC is shared between two VGAs, with each VGA differential output sampled on alternate clock cycles, making the effective sampling rate 32.5 Msamples/s. At that rate, it sips only 39 mW/channel, but it’s possible to scale down the sampling rate for even lower power consumption.

With eight VGAs and eight 12-bit ADCs with low-voltage differential signaling (LVDS) data outputs, the AFE5801 consumes 50 mW/channel at 30 Msamples/s and 58 mW/channel at 50 Msamples/s. The TI architecture allows each channel’s low-noise amplifier (LNA) to be located at the probe end of the cable, rather than in the ultrasound box. Both devices come in 9- by 9-mm packages. They join TI’s existing lineup, which was announced last March.

A Daring Competitor

With TI and Analog Devices duking it out for dominance in the front ends of the world’s ultrasound medical devices, it would take some audacity for a fabless startup to design its first product for the same market. But Samplify Systems has announced chips based on a lossy data-compression algorithm (“Hardware Algorithm Fine-Tunes Converters For Best Compression,” ED Online 8691).

The essential point of Samplify’s approach is that it isn’t necessary to digitize every bit as long as you have a decent model of the kind of data you’re looking at. Samplify’s audacious SAM1600 family of 16-channel, 12-bit, 65-Msample/s ADCs integrate the company’s Prism data-compression technology (see the figure). There are full 16-channel versions and versions that share the ADCs between clock cycles.

Packaging is a 12- by 12-mm ball-gird array (BGA). Power consumption is 44 mW per channel. The Prism technology reduces the number of LVDS I/O pairs, and thus the power they consume, by up to 75%. While initial uses will focus on ultrasound, potential applications include 4G wireless basestations, automated test equipment, and radar/sonar receivers.

A key selling point is that system designers aren’t necessarily starting from ground zero with Samplify. The company has been working with FPGA vendors on the decompression side, so the FPGA vendors already have Samplify decompression blocks in their libraries. Audacity doesn’t mean not laying one’s groundwork.

Samples of the SAM1600 family of devices are available now from Samplify or its distribution partners. The SAM1610, SAM1605, and SAM1600 cost $79.00, $39.50, and $64.00 in 1000-unit quantities, respectively. Customers using any of the chips receive a royalty-free license to the company’s decompression FPGA IP or software. A complete ADC evaluation board with data analysis software is also available for $1995.00.


Texas Instruments


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