First Look:

Zarlink brings Wi-Fi networks  to "in-body" communications 

By Bernard Cole
iApplianceWeb
(05/31/05, 12:54:52 AM GMT)

Ottawa, Canada – Wi-Fi chip specialist Zarlink Semiconductor has developed what it claims is the world’s first transceiver chip designed exclusively for “in-body” wireless communication systems that link implanted medical devices and base stations.

Designated the ZL70100, it is designed to deliver high-speed 500 kb/s data transmission over a typical two-meter range versus previous magnetically coupled in-body systems capable of only a 10 centitemeter range and data rates of only a few tens of kilobits per second. kb/s.

It is designed to support industry-leading transmission rates of 800 kb/s for raw data and 500 kb/s for usable data, while consuming less than 5 mA (milliamps) of supply current while active. With the ability to aggressively duty-cycle the radio transceiver, the ZL70100 allows implanted devices to quickly transmit large amounts of patient health and device performance data with minimum impact on the battery life of the implanted device.

The new device is targeted at applications using the Medical Implant Communications Service (MICS), an ultra-low power, unlicensed, mobile radio service for transmitting data in diagnostic or therapeutic applications associated with implanted medical devices. MICS permits individuals and medical practitioners to utilize ultra-low power medical implant devices, such as cardiac pacemakers and defibrillators, without causing interference to other users of the electromagnetic radio spectrum.

According to Steve Swift, senior vice president and general manager, Ultra Low-Power Communications, Zarlink, advances in ultra low-power radio expertise and global adoption of the MICS 402-405 MHz frequency band for implanted  communications has opened the door for advanced telemedicine applications that extend patient health monitoring beyond  the traditional clinical setting.

“Physicians can use MICS technology to remotely monitor patient health without requiring regular hospital visits,” he said. “For example, an ultra low-power RF  transceiver in a pacemaker can wirelessly send patient health and device  performance data to a bedside base station in the home.

“Data is then forwarded over the telephone or Internet to a physician’s office, and if a problem is detected the patient goes to the hospital where the high-speed two-way RF link can be used to easily monitor and adjust device performance.”

During surgery, a physician can use the higher data rates and longer

communication range afforded by MICS technology to program the performance of an implanted device outside of the sterile surgical environment.

Compared to current MICS approaches, said Swift, the technology Zarlink uses provides several orders of magnitude increase in data transmission rate and communication range and ensures implanted medical device manufacturers can  design systems that meet strict global standards.

“The higher data rate and extended communication range of our radio transceiver enables advanced in-body communication systems, such as implanted blood glucose sensors controlling insulin intake for diabetes patients, networked stimulators restoring lost limb function or pacemakers using the high-speed wireless link to signal emergency response during a cardiac event,” said Smith.

Since most implanted medical devices do not require constant communication, and instead transmit data on a scheduled or as-required basis, the average “sleep” current was a key design factor, Smith said, so the ZL70100 radio transceiver contains an ultra low-power wake-up system with an average current demand of just 200 nA (nanoamps).

The chip requires just two external components excluding antenna matching, allowing manufacturers to use circuit substrate  space savings to increase battery size and support advanced functionality while also lowering BoM (Bill of Material) costs.

The ZL70100 ultra low-power transceiver chip fully meets the MICS standard defined by the FCC (Federal Communications Commission) and ETSI (European Telecommunications Standards Institute). No other commercially available chip for implanted communication systems, said Swift,  matches the data rate, ultra low-power performance and high level of integration delivered by the ZL70100 transceiver.

He said the industrial-grade ZL70100 transceiver chip for base stations is the first device in a product platform designed specifically to meet the performance, power and size requirements of implanted communication systems. Qualification of the same transceiver chip for implantable applications is currently underway, and this device will be available later this year.

To learn more, go to http://ulp.zarlink.com/.