AS3911B Datasheet, PDF (1/155 Pages) ams AG – NFC Initiator / HF Reader IC

General Description
AS3911B
NFC Initiator / HF Reader IC
The AS3911B 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 like MIFARE™ Classic¹ is possible
through using the AFE and implementing framing in the
external microcontroller (Stream and Transparent modes).
Compared with concurrent NFC devices designed with the
mobile phone in mind, the AS3911B 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 Automatic Antenna Tuning technology, the
device is optimized for applications with directly driven
antennas. The AS3911B is alone in the domain of HF Reader ICs
in that it contains two differential low impedance (1Ω) antenna
drivers.
The AS3911B includes several features, which make it
incomparable for low power applications. It contains a low
power capacitive sensor, which can be used to detect the
presence of a card without switching on the reader field.
Additionally, the presence of a card can also 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 the system after a defined time period and
check for the presence of a tag using one or more techniques
of low power detection of card presence (capacitive, phase or
amplitude).
The AS3911B is designed to operate from a 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.
Ordering Information and Content Guide appear at end of
datasheet.
1. MIFARE™ and MIFARE™ Classic are trademarks of NXP B.V
ams Datasheet: 2014-Jun-12 [v1-08]
AS3911B – 1