Sensor-enabled RFID tags extend wireless data-logging beyond identification

The SL13A is an ISO15693-compliant tag for use with near field communications (NFC-V) and highfrequency radio-frequency identification (HF RFID) readers. The SL900A is an EPC Gen 2 Class 3 tag for use with RFID readers.

The devices include an on-board temperature sensor, an interface to an external sensor, and can operate in passive (batteryless) mode. In this mode, the tag harvests energy from a reader’s broadcast, using the power to read the temperature or data from an external sensor, and transmits the information back to the reader together with a unique ID. The data is time-stamped by the reader.

The SL13A and SL900A can be powered by a single-cell or 3V battery. In battery-assisted passive (BAP) mode, the tag’s on-board real-time clock is enabled, and can be used to trigger periodic sensor readings. Up to 762 (SL13A) or 841 (SL900A) time-stamped events may be saved in the on-chip EEPROM, from where they may be read when the device is in range of a reader.

The combination of a sensor interface, NFC compatibility and support for passive mode offers designers the opportunity to invent new kinds of wireless data-logging applications, or to find better ways to implement existing data-logging systems. Applications as diverse as patient monitoring, building control and automotive safety can benefit from the ability to read bio-medical, humidity or pressure measurements via the SL13A using harvested energy from an NFC reader such as an Android smartphone or tablet.

Both the SL13A and SL900A feature a serial peripheral interface for connection to a microcontroller. They can operate from a power supply ranging from 1.2V to 3.6V. The tags provide for very long battery life, drawing a typical 1.6μA in stand-by mode with the real-time clock running. The on-board temperature sensor is accurate to up to 0.5%.

Oluf Alminde, Senior Marketing Manager for the Power & Wireless Business Unit of ams, said: “RFID tags are ideally suited for many applications in the transportation, logistics and retail sectors for simple passive, battery-less identification of objects. The SL13A and SL900A represent the next generation of RFID tag, allowing the reading of identification data, as well as temperature and many other environmental conditions.”

For medical equipment OEMs, the SL13A and SL900A offer opportunities for exciting new applications, such as an NFC sensor tag that can be safely and easily implanted or swallowed, enabling patients to monitor specific physiological conditions around the clock, reading data simply by holding an NFCenabled phone or tablet close to the body.

Price & Availability

The SL13A and SL900A sensor-enabled RFID tags are in volume production now. The SL13A is priced at $2.59 and the SL900A at $3.63 for 1,000 pieces.

Technical Support

A demonstration kit, the SL13A-DK-STQFN16, is available for the SL13A. The SL900A DK demo kit is for the SL900A. Both are available online from ams, priced at $55. For further information on the SL13A or SL900A or to request samples.