Boosted NFC tag front end enables secure payment transactions on uSD and uSIM cards

March 06, 2013 // By Paul Buckley
ams AG has released a tag analog front end (AFE) which enables the operation of NFC on µSD, µSIM, SIM and other space-constrained carrier devices.

Featuring Active Boost technology from ams, the AS3922 emulates an ISO14443A/B tag through active transmission of the tag’s response in synch with the reader’s carrier field. This overcomes the difficulties with using conventional passive load modulation in a µSD or µSIM card, a device with a very small antenna and – in a mobile phone – operating in a harsh environment. The use of an AS3922 AFE provides for tag-to-reader communication at coupling factors one order of magnitude lower than is possible using conventional methods.

The general introduction of the AS3922, which can interface to any Dual Interface Secure Environment, enables the development of a new generation of contactless payments accessories hosted on a µSD, µSIM or SIM card. Mobile phone network operators, banks and others will be able to provide customers with a contactless payment technology card suitable for the many mobile phones that have no NFC (Near Field Communications) capability.

As well as offering Active Boost functionality, the AS3922 also features antenna auto tuning (AAT) technology, Q factor adjustment, and a low-impedance output driver with adjustable output power.

The AS3922 complies with the ISO14443A and B standards for tag emulation, supporting data rates up to 106kb/s. It also supports FeliCa at data rates up to 212kb/s.

The AS3922 provides an Analog Contactless Bridge (ACLB) interface for communication with a secure element and a Digital Secure Environment Interface which supports NFC CLF, DCLB and NFC-WI interfaces.


The AS3922 is in volume production now.

A demonstration board for evaluating the AS3922 is available on request from ams.

More information about the AS3922 analog front end at