NFC sol'n from Ams, ST targets IoT nodes, wearables

Ams AG has revealed that its boostedNFC technology that enables reliable NFC coupling in space-constrained devices has been implemented in a complete system development board compatible with the STM32 family of MCUs from STMicroelectronics.

The NFC expansion board released by ST, which plugs into Nucleo STM32 main boards, offers a complete design blueprint for implementing NFC in applications such as IoT nodes, in which NFC can be used for configuration and network commissioning, and wearable devices, in which it may securely carry data for contactless payments, ticketing or access control.

The expansion board is supplied with a full suite of NFC firmware provided by ST for its family of ARM Cortex-M based STM32 MCUs. The NFC board is complemented by other expansion boards implementing fingerprint recognition, Bluetooth connectivity, M2M communications and a display, to enable rapid prototyping of a complete NFC-enabled end product.

ST's NFC expansion board is based on the Ams AS39230 boostedNFC analogue front end, and ST's own ST54E system-in-package (incorporating the ST21NFCC controller and the ST33G1M2 Secure Element). Depending on application requirements, the board can be connected to various antenna sizes, ranging from 400mm² supporting NFC Reader/Writer functionality down to ultra-tiny SMD antennas for Card Emulation-only functionality.

The circuit implemented in the board provides outstanding NFC performance in conditions hostile to RF signals, for instance when operating close to or inside metal surfaces, or when transmitting through a very small antenna. Designers of IoT nodes and wearables, for instance, often have to enclose their devices in metal housings, or must accommodate an antenna inside an extremely small enclosure. The expansion board gives them a ready-made NFC implementation that will achieve fast, reliable coupling with any standard NFC reader, such as smartphones, contactless payment terminals, transit system entry barriers and access control card readers.

The design implemented in the expansion board is also suitable for use in applications that require worldwide certification, including for Common Criteria, EMVCo, GlobalPlatform, and Visa, Mastercard, Amex and the People's Bank of China (PBoC). It enables OEMs using an STM32 MCU to quickly implement a design for a wearable device such as a wristband or smart watch, which can be used to pay for goods at contactless payment terminals, to emulate smart cards such as metro transit ticket cards, or to perform access control functions such as keyless entry to hotel rooms.

The excellent RF performance of the NFC expansion board is due to the active load modulation method of boosting the NFC signal implemented in the AS39230, stated the company. This produces an operating volume some 10 times larger than the passive load modulation method used in smart cards. At the same time, the AS39230 based system draws as low as 15µA average current in listening mode, thus draining far less power from the battery than conventional NFC solutions.

AS39230 block diagram

The secure NFC expansion board is available from ST. The AS39230 NFC AFE is available in production volumes from Ams. Unit pricing is available on request.