Implementing instant, high-speed Near Field Communication (NFC) between two independent devices has been made easier and cheaper with the introduction of the AS3953 interface chip from ams. The new AS3953 offers a high data-rate interface between a NFC device such as a smartphone and any host microcontroller with a standard Serial Peripheral Interface (SPI).
Operating on energy harvested from an NFC reader’s RF emissions, the AS3953 NFiC (Near Field Communications interface Chip) requires no external power source and at most one external component (a capacitor). The device enables system designers to add full bi-directional NFC capability at a total cost less than half that of a typical NFC reader implementation, which can require as many as 20 external components.
The AS3953 is fully compliant with NFC Forum specifications (NFCIP-1 target at 106kbps) and the ISO14443A industry standard (up to 848kbps, to Level 4). This means that it can be used in contactless smart cards and as an NFC Forum-compatible interface tag, and can establish instant communication with any NFC-enabled phone in close proximity (<10cm).
The AS3953 is expected to find uses in a wide variety of applications, including contactless passive programming of MCU-based systems, smart cards with displays, smart retail shelf labels, sensors and ultra low-power data loggers, medical devices, and secured NFC Bluetooth pairing.
It can also enable new approaches to system designs by using an NFC-enabled smartphone as a display host and system controller for normally stand-alone devices, eliminating the requirement for the slave device to have its own display and processor.
The AS3953 features a configurable wake-up interrupt, enabling a zero-power system design while in shut down. It also contains a complete analogue front end, 1kB of internal EEPROM, and a 4-wire SPI with a 32-byte FIFO. The device can draw up to 5mA of harvested energy from the external magnetic field, and includes an internal power management circuit that can supply harvested energy to the application making it suitable for use with battery-powered and portable microcontroller-based devices.
Commenting Rene Wutte, Marketing Manager at ams, said that “The AS3953 creates a whole new category of NFC applications. It allows NFC functionality to be added to any application for a fraction of the cost of a full NFC reader, without complicating the design. This is now, for instance, the easiest and most affordable way to enable an application to communicate with a mobile phone.”
ams has also announced a new reference design developed in close cooperation with Epson. The design is for a complete passive solution for price labels and smart cards. It combines an Epson S1C17F57 microcontroller, which features a built-in driver for e-paper displays (64 channels), and the AS3953 NFiC from ams.
According to Manfred Wittmeir, IC Department Manager at Epson Europe Electronics GmbH, “The AS3953 enables us for the first time to build a complete passive solution without the need for an auxiliary power supply such as a battery, while implementing a standard NFC interface for exchanging data with our microcontroller. A simple design, it can be implemented quickly by engineers with no deep knowledge of the operation of NFC technology.”