Zarlink Semiconductor Inc. has introduced a transceiver chip ZL70101, an ultra low-power RF system-on-a-chip solution, for use in both implanted medical devices and monitoring base stations Built on its MICS technology platform, the ZL70101 transceiver chip delivers high data rates, low power consumption and unique wake-up circuitry. According to Zarlink, previous home health-monitoring systems required the patient to accurately position an inductive wand over the implanted device. In comparison, using Zarlink MICS technology, patient health and implanted device performance data can be stored in the implanted medical device’s memory and wirelessly transmitted to a base station, without requiring patient intervention. Data can then be forwarded over the telephone or Internet to a physician’s office. If a problem is detected, the physician will schedule a patient follow-up visit where the two-way RF link can be used to interrogate and adjust implanted device performance.

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During surgery to implant medical devices, the longer operating range of the ZL70101 chip allows the base station/programmer to be located outside the sterile environment. This potentially shortens surgery times and reduces healthcare costs, as programming equipment does not have to be sterilized for use in the operating room, said the manufacturer.

The ZL70101 transceiver incorporates a unique “wake-up” receiver that allows the integrated circuit to operate in an extremely low current 250 nA “sleep” mode. Communication is then initiated using a specially coded wake-up signal from the base station transmitter. The implanted medical device can also wake up the ZL70101 radio on detection of an emergency medical event. An emergency signal could then be sent to the base station, which in turn could directly alert paramedics.

When in full operation the ZL70101 typically consumes 5 mA (milliamps) of supply current. By using the high data rate with heavy duty-cycling, the average power consumed by the ZL70101 can be very small. This conserves overall implanted medical device battery life.

The highly integrated ZL70101 system-on-chip includes a MAC that implements a communication protocol specifically designed for the requirements of high-reliability implanted medical devices and is fully compliant to current MICS standards. The MAC protocol includes Reed-Solomon forward error correction together with cyclical redundancy check (CRC) error detection and retransmission to achieve an extremely reliable data link. The chip requires just three external components, excluding antenna matching, allowing device manufacturers to use board space savings to increase battery size and support advanced functionality while lowering overall system BoM cost.

It is available as implantable-grade wire-bondable die or in a 48-pin QFN package for the non-implanted base station applications. The chip is fully supported by a reference system and application development kit.