Product overview
Description
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.
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All 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 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, 5x5 mm package with wetable flank or wafer delivery
eDesignSuite
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NFC Inductance
Input geometry and substrate properties Get antenna impedance 
UHF Link Budget
Enter forward and reverse link characteristics The tool returns link budget estimate 
NFC Tuning Circuit
Enter antenna parameter and matching target Select the topology of the matching network The tool returns component values for the desired design targets You might also like...
Featured Videos
ST25 NFC accessory detection video from embedded world 2018
ST25DV-I2C discovery kit demonstration using ST25R3911B reader
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STMicroelectronics - ST25R3911B
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Quality and Reliability
| Part Number | Marketing Status | Package | Grade | RoHS Compliance Grade | Material Declaration** |
|---|---|---|---|---|---|
| ST25R3911B-AQFT | Active | VFQFPN 32 5x5x1.0 mm | Industrial | Ecopack2 | |
| ST25R3911B-AQWT | Active | VFQFPN 5X5X1 32L WETTABLE FLANKS | Industrial | Ecopack2 | |
| ST25R3911B-ASWB | Active | US WF V.I. | Industrial | N/A | |
(**) The Material Declaration forms available on st.com 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.
Sample & Buy
| Part Number | Marketing Status | Budgetary Price (US$)*/Qty | Order from ST | Order from distributors | Package | Packing Type | RoHS | Country of Origin | ECCN (US) | ECCN (EU) | Temperature (°C) | Free Samples | ESample Max Qty | Operating Temperature (°C) (min) | Free Samples | ESample Max Qty | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| min | max | |||||||||||||||||
| ST25R3911B-AQFT | | | distributors No availability of distributors reported, please contact our sales office | VFQFPN 32 5x5x1.0 mm | Tape and Reel | THAILAND | EAR99 | NEC | -40 | 125 | - | - | -40 | - | - | |||
| ST25R3911B-AQWT | | | distributors No availability of distributors reported, please contact our sales office | VFQFPN 5X5X1 32L WETTABLE FLANKS | Tape and Reel | THAILAND | EAR99 | NEC | -40 | 125 | - | - | -40 | - | - | |||
| ST25R3911B-ASWB | | | distributors No availability of distributors reported, please contact our sales office | US WF V.I. | Not Applicable | CHINA | EAR99 | NEC | -40 | 125 | - | - | -40 | - | - | |||
ST25R3911B-AQFT Active
ST25R3911B-AQWT Active
ST25R3911B-ASWB Active
(*) Suggested Resale Price (USD) per defined quantity for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office or our Distributors