TI AFE measures both weight and body composition

Texas Instruments Inc. unveiled the industry's first analog front end that integrates two separate signal chain front ends for weigh scale and dual body composition measurements into a single device.

The AFE4300 front-end solution is aimed at engineers designing weigh scales that incorporate body composition meters, body impedance analyzers, and impedance measurement equipment to get their products to market faster than by implementing existing, more complex multi-chip solutions.

“We want to enable all of these customers who are trying to get into the fitness type products with a device that will eliminate them having to build in-house expertise on how to do body composition,” said Karthik Soundarapandian, systems manager for the health and fitness segment, medical business unit,  Dallas. “They can easily integrate [the function] into existing weigh scales or if they are thinking of putting it as an accessory.”

The AFE4300 incorporates two separate signal chains, one targeting weight measurement and the other targeting body composition analysis, with a 16-bit, 860-sps A/D converter multiplexed between them. The device's three BCM channels enable segmental body impedance analysis (BIA) between body extremities, which allows for a full picture of the subject's body composition.

TI is targeting the mid-range weigh scale market, in which products cost between $100 and $150. Designs are changing to add wireless capability so users can easily track their body composition, Soundarapandian said. With the AFE43000, designers can add a microcontroller and low-power Bluetooth wireless chip to enable this capability.

The AFE4300 consumes less than 1 mA, operating from a 2-V to 3.6-V power supply, to extend battery life.

The AFE4300's tetra-polar measurements eliminate electrode impedance-related inaccuracies. In addition, the device's three BCM channels enable segmental body impedance analysis (BIA) for measurement across the body including hand to hand, foot to foot, or even hand to foot, which increases overall measurement accuracy. The device also includes an option to accurately measure Extra Cellular Water (ECW) and Intra Cellular Water (ICW) using bio-impedance spectroscopy (BIS).

The AFE4300 is available now in a 12-mm x 12-mm TQFP-80 package. It is priced at $2.50 in quantities of 1,000.

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