New Industry Products

Energy-Harvesting-Powered Sensor Interface for Industrial IoT

November 01, 2017 by Paul Shepard

ams has released the AS3956, a dynamic NFC sensor tag IC which meets industrial-grade quality standards and provides very high reliability in mission-critical applications and in products with a long operating lifetime.

The AS3956 dynamic tag acts as a contactless bridge between sensors and any NFC reader, such as a smartphone, through a host microcontroller. It supports the NDEF messaging protocol in full compliance with NFC Forum recommendations, guaranteeing interoperability with any NFC phones, including Apple® iOS devices.

The AS3956 includes an energy-harvesting capability, drawing energy from the incoming RF field generated by an NFC reader, and supplying up to 5mA to an external device. Energy harvesting is particularly useful as a cost effective, small footprint alternative to standard wireless charging, to extend battery lifetime in biometric smart cards, or to implement fully passive wireless sensing solutions, as required for example in smart insulin pens.

AS5172 Block Diagram (click on image to enlarge)

In designing the robust AS3956, ams drew on close interaction with customers that manufacture products for industrial applications and the Internet of Things (IoT). Intensive testing in real-world applications has validated the performance and reliability of the chip in a wide range of demanding operating conditions.

Unlike the consumer-grade dynamic NFC tags on the market today, the AS3956 is suited to:

  • Industrial and Internet of Things (IoT) applications exposed to harsh operating conditions, including extreme temperatures ranging from -40°C to 125°C;
  • Products requiring an extended operating lifetime, such as HVAC equipment, hearing aids, and wireless sensors for infrastructure such as roads, bridges and utilities. The AS3956’s internal EEPROM memory is rated for a minimum 100,000 program/erase cycles, and offers 10 years’ data retention at 125°C;
  • Mission-critical products that require a zero failure rate.

The AS3956 includes various features that give the designer flexibility in implementing NFC-based applications. These include the provision of both an I2C and an SPI interface to a host microcontroller, and a wide supply voltage range of 1.65V-5.5V.

In basic operation, the AS3956 acts as a stand-alone Type 2 tag conforming to the NFC Forum standards and supporting NFC communication with a reader. In addition, either of two data-transfer modes for host controller communication can be selected:

  • Extended Mode, a self-timed data transfer mechanism using standard Type 2 tag commands, thus minimizing software overhead on the host controller
  • Tunneling Mode to implement ISO14443A Level 4 PICC emulation in line with EMVCo requirements or custom protocols

“Previous generations of general purpose NFC dynamic tags have not offered the reliability and flexibility that many applications require. The AS3956 offers far superior lifetime performance. The rigorous quality processes and numerous validation tests put in place by ams will give customers confidence that the AS3956 can cope with operation in harsh or extreme conditions and still maintain unimpaired RF, interface and memory functions,” said Giancarlo Cutrignelli, Head of Marketing for Wireless Sensor Nodes at ams.

ams provides the AS3956 in a miniature chip-scale package (CSP) just 0.3mm high, and with a 1.8mm x 1.4mm footprint as well as in a 3mm x 3mm MLPD package. It is available for sampling now. Unit pricing is $0.53 in an order quantity of 1,000 units.