The ST25R3911B is a highly integrated NFC Initiator / HF Reader IC, including 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 14443A and B reader (including high bit rates), ISO 15693 reader and FeliCa™ reader. Implementation of other standard and custom protocols like MIFARE™ Classic is possible using the AFE and implementing framing in the external microcontroller (Stream and Transparent modes).

The ST25R3911B is positioned perfectly for the infrastructure side of the NFC system, where users need optimal RF performance and flexibility combined with low power.

Thanks to automatic antenna tuning (AAT) technology, the device is optimized for applications with directly driven antennas. The ST25R3911B is alone in the domain of HF reader ICs as it contains two differential low impedance (1 Ohm) antenna drivers.

The ST25R3911B includes several features that make it very suited for low power applications. It contains a low power capacitive sensor that can be used to detect the presence of a card without switching on the reader field. 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 the stored reference. It also contains a low power RC oscillator and wake-up timer that can be used to wake up the system after a defined time period, and to check for the presence of a tag using one or more low power detection techniques (capacitive, phase or amplitude).

The ST25R3911B is designed to operate from a wide (2.4 V to 5.5 V) power supply range; peripheral interface IO pins support power supply range from 1.65 V to 5.5 V.

Key Features

  • ISO 18092 (NFCIP-1) Active P2P
  • ISO14443A, ISO14443B, ISO15693 and FeliCa™
  • Supports VHBR (3.4 Mbit/s PICC to PCD framing, 6.8 Mbit/s AFE and PCD to PICC framing)
  • Capacitive sensing - Wake-up
  • Automatic antenna tuning system providing tuning of antenna LC tank
  • Automatic modulation index adjustment
  • AM and PM (I/Q) demodulator channels with automatic selection
  • DPO (Dynamic Power Output)
  • Up to 1.4 W in case of differential output
  • User selectable and automatic gain control
  • Transparent and Stream modes to implement MIFARE™ Classic compliant or other custom protocols
  • Possibility of driving two antennas in single ended mode
  • Oscillator input capable of operating with 13.56 MHz or 27.12 MHz crystal with fast start-up
  • 6 Mbit/s SPI with 96 bytes FIFO
  • Wide supply voltage range from 2.4 V to 5.5 V
  • Wide temperature range: -40 °C to 125 °C
  • QFN32, 5 mm x 5 mm package


Technical Documentation

Product Specifications
Description Version Size
DS11793 DS11793: High performance HF reader / NFC initiator with 1.4 W supporting VHBR and AAT 4.0 2 MB
Application Notes
Description Version Size
AN4974 AN4974: Antenna matching for ST25R3911B/ST25R391x devices 2.0 3 MB
AN4914 AN4914: Automatic Antenna Tuning (AAT) of ST25R3911B/ST25R391x devices 2.0 1 MB
AN5043 AN5043: Layout recommendations for the design of boards with ST25R3911B/ST25R391x devices 4.0 873 KB
AN4985 AN4985: Wake-up mode of the ST25R3911B/ST25R391x 1.0 805 KB

Presentations & Training Material

Description Version Size
ST25R series overview 1.0 3 MB

Publications and Collaterals

Description Version Size
High performance NFC/RFID readers 1.0 981 KB
Description Version Size
NFC solutions from ST 1.0 3 MB

Tools and Software

STM32 Open Development Environment
Embedded Software
ST25 - NFC / RFID Software
Evaluation Tools
Product Evaluation Tools
Get Started Support & Community

Sample & Buy

Part Number Package Packing Type Marketing Status Unit Price (US$) * Quantity ECCN (EU) ECCN (US) Country of Origin More info Order from ST Order from Distributors
ST25R3911B-AQFT VFQFPN 5X5 32L PAD 3.5X3 PUNCHED Tape And Reel Active 3.3 1000 NEC EAR99 - MORE INFO Get Sample Add to cart DISTRIBUTOR AVAILABILITY
ST25R3911B-ASWB US WF V.I. Not Applicable Active - - NEC EAR99 - MORE INFO No availability reported, please contact our Sales office

(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office  or our Distributors

Quality & Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
ST25R3911B-AQFT ActiveVFQFPN 5X5 32L PAD 3.5X3 PUNCHEDIndustrialEcopack2 0 0
ST25R3911B-ASWB ActiveUS WF V.I.IndustrialEcopack2

(**) The Material Declaration forms available on may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.