The ams AS3911 is a highly-integrated NFC Initiator / HF Reader IC. It includes the analog front end (AFE) and a highly integrated data framing system for ISO 18092 (NFCIP-1) initiator, ISO 18092 (NFCIP-1) active target, ISO 14443 A and B reader (including high bit rates) and Felica™ reader. Implementation of other standard and custom protocols is possible through using the AFE and implementing framing in the external microcontroller (Transparent mode).
Compared with concurrent NFC devices designed for the mobile phone in mind, the AS3911 is positioned perfectly for the infrastructure side of the NFC system, where users need optimal RF performance and flexibility combined with low power. With ams' unique AAT technology, it is optimized for applications with directly driven antennas. The AS3911 is alone in the domain of HF Reader ICs in that it contains two differential low impedance (1 Ω) antenna drivers.
The AS3911 includes several features, which make it incomparable for low power applications. It contains a low power capacitive sensor, which can be used to detect a presence of a card without switching on the reader field. Additionally, a presence of a card can be detected by performing a measurement of amplitude or phase of signal on antenna LC tank and comparing it to stored reference. It also contains a low power RC oscillator and wake-up timer which can be used to wake system after defined time period and check for a presence of a tag using one or more techniques of low power detection of card presence (capacitive, phase, or amplitude).
The AS3911 is also qualified for use in automotive applications, which makes it ideal for car access, ignition, and diagnostic functions. The AS3911 is designed for operation from wide power supply range from 2.4 V to 5.5 V, peripheral interface IO pins support power supply range from 1.65 V to 5.5 V.