Freescale MCUs pave SoC path to medical devices

PORTLAND, Ore. — Freescale Semiconductor announced five microcontrollers for medical applications Tuesday (April 27) at the Embedded Systems Conference, promising a system-on-chip approach to handheld medical device operation.

Ultralow-current modes in the Flexis MCUs allow up to five-year battery lifetimes, the company said. Freescale also guarantees that it will manufacture the chips for 15 years to support the long product life spans of medical devices.

"The real secret sauce is the measurement engine that we have added to replace an application's need for discrete components," said John Weil, global product and enablement manager at Freescale. The integrated measurement engine meets the application requirements for blood glucose meters, heart rate monitors and other diagnostic and therapeutic medical gear.

The engine contains a 16-bit analog-to-digital converter, 12-bit digital-to-analog converter, transimpedance amplifiers, operational amplifiers, high-precision voltage reference, analog comparator, programmable reference (low-power wakeup) and programmable delay block (for synchronizing A/D and D/A operations).

The microcontrollers feature either 8- or 32-bit data paths as well as options for LCD drivers and USB, using the Personal Health Care Device USB stack designed to the Continua Health Organization standards.

Weil said the medical microcontrollers are priced at "only a few dollars" and "can save up to $4" in bill-of-materials costs for medical systems. "All you need to do is add a biosensor" to complete the design, he said.

Freescale says its device meets the accuracy requirements set by the U.S. Food and Drug Administration and that it includes two tri-amps and two op amps to meet FDA requirements for redundancy in the sensors used for medical apps. By applying the precision voltage reference with the A/D converter, the microcontrollers can accommodate both static- and dynamic-probing-signal biosensors.

Medical OEMs can prototype their gear using the Freescale Tower System modular development platform and CodeWarrior Development Studio software, and can deploy their systems using the Freescale MQX real-time operating system.