May 21 2015
ams AG, a leading provider of high performance sensors and analog ICs, today launched the AS3955, an NFC interface chip (NFiC™) which offers unique energy harvesting and data transfer capabilities.
PA AS3955 NFC
Like its predecessor the AS3953, the AS3955 provides a contactless bridge between an NFC reader (for instance, a smartphone or tablet) and any microcontroller. But the AS3955 can also act as a power supply for the host device, harvesting as much as 5mA at 4.5V – enough to charge a Li-ion cell battery – from the RF energy radiated by an NFC reader.
The AS3955 also offers the designer a choice of two bi-directional data transfer modes. The Extended mode allows the use of standard NFC tag commands to transfer data with minimum processing overhead on the host microcontroller. A second mode, the Tunneling mode, provides a transparent and fully flexible channel between the reader and the host microcontroller, leaving the user free to implement any standard or proprietary communication protocol. Neither mode requires data buffering in the AS3955’s internal EEPROM memory, resulting in faster data transfers.
The AS3955 features a high performance RF front end, which connects to a simple external NFC antenna without additional external components required. It also includes an EEPROM memory (of 2kbits or 4kbits) and an SPI or I2C interface for communication with an external microcontroller.
The device is fully compliant with ISO14443A standard up to level 4, and with NFC Forum specifications, supporting both Type 2 Tag stand-alone functionality, and Type 4 Tag emulation in combination with an external MCU.
The AS3955 offers unrivaled performance and flexibility thanks to energy and data management features that are superior to those of existing interface tags on the market. The energy that the AS3955 harvests from an NFC reader enables it to operate with no external power supply. This harvested energy can also be used to power external circuitry. This enables the implementation of stand-alone, eco-friendly, battery-less product designs, such as wireless sensor interfaces, interactive games and toys, smart price tags in shops and smart payment cards.
A unique data management feature provided by the AS3955 is its new Stealth mode: this enables the host MCU to deactivate the NFiC’s RF channel via the I2C or SPI interface after an operation such as Bluetooth pairing has been completed successfully. This provides for guaranteed user control of NFC operation. The AS3955 also offers 32-bit password protection of its EEPROM memory.
Furthermore, the AS3955 adds a new Silent mode for fail-safe Bluetooth pairing. If the host’s battery has insufficient remaining charge to power its Bluetooth module, the AS3955 NFiC automatically disables its RF circuitry to prevent the device from initiating a pairing procedure.
These superior energy and data management features find a wide range of uses in industrial, consumer and gaming equipment. Products can be configured or personalized, for instance at the end of a factory’s production line, without the need to be powered. The high transfer speed and energy harvesting capability reduces the time taken to download configuration data, helping to increase throughput in high-volume manufacturing lines.
‘Existing interface tags might be adequate if all you need is a simple, slow NFC link to a microcontroller. The AS3955, however, gives designers the scope to implement far more sophisticated systems because of its ability to act as the host device’s power supply, and because of its advanced data transfer modes. The AS3955 is designed to be deployed in a range of new applications that have not previously been able to use an interface tag,’ said David Renno, Product Marketing Manager at ams.
The NFC interface tag IC AS3955 is available now in production volumes in a 10-pin, 3mm x 3mm MLPD package.
Wafer-level chip scale package (WL-CSP) and sawn wafer are available on request. In the WL-CSP version, unit pricing is $0.98 in an order quantity of 1,000 pieces.
A demonstration board for the AS3955 is available online from the ams ICdirect web store.