ST25R3916B Mini V2 is a compact ELECHOUSE 13.56 MHz NFC and HF RFID reader module. Its small 27 x 20 mm board and external antenna are suitable for space-constrained embedded products.
V1-compatible upgrade: V2 retains the same board dimensions, mounting-hole layout, communication connector and pinout as V1, and is compatible with V1 software. Reuse your existing V1 mounting, wiring and software, with the host interface set to match your application. V2 ships in I2C mode; select SPI when replacing a V1 setup that uses SPI.
The module includes a 52 x 5.5 mm / 700 nH FPC antenna with anti-metal backing film. Other antennas are sold separately.
Key features and V2 improvements
- Improved power supply design for more stable operation.
- I2C by default, with SPI available by cutting the marked jumper bridge.
- Improved I2C pull-up circuit for more stable SPI communication.
- Added spare IPEX antenna connector alongside the ST1.0 2P connector.
- Supports NFC-A (ISO 14443A), NFC-B (ISO 14443B) and NFC-V (ISO 15693).
- Single-antenna design: connect one external antenna at a time.
Specifications
| Reader IC | STMicroelectronics ST25R3916B |
|---|---|
| Operating frequency | 13.56 MHz |
| Module size | Approximately 27 x 20 mm |
| Host interface | I2C by default; selectable SPI |
| I2C address / recommended clock | 0x50 (7-bit) / 100 kHz |
| SPI mode / maximum clock | Mode 1 / 10 MHz |
| Supply input | 3.3-5 V DC |
| Digital IO level | Nominal 3.0 V; use level shifting for 5 V GPIO |
| Included antenna | 52 x 5.5 mm / 700 nH FPC, with anti-metal backing film |
| Antenna connections | ST1.0 2P, spare IPEX and solder points; one shared antenna channel |
| Read/write range example | 45 mm with the included antenna and an 85 x 55 mm MIFARE S50 card |
| Package weight | 20 g |
Actual read/write range depends on the card, antenna, cable and installation. See the datasheet for the full antenna and card comparison.
Antenna options and customization
Choose an antenna to suit your enclosure and target card. The external-antenna design supports slim, rectangular and round FPC antennas, as well as larger PCB antennas for applications that need more range.
- Included: 52 x 5.5 mm / 700 nH FPC antenna with anti-metal backing film, suitable for narrow installation spaces.
- More choices: Alternative FPC antennas are sold separately. Other antenna sizes can be customized.
- Application-specific tuning: Optimization for a particular antenna, tag or combination is available as a customization service for volume projects. The standard module is not optimized for every antenna and tag.
V2 uses one antenna channel. The ST1.0 2P connector, spare IPEX connector and solder points provide alternative connection locations. Connect one antenna at a time.
Read/write performance with different antennas
The included slim FPC antenna measured 65 mm with an 85 x 55 mm ISO14443B card. With a separate 311 x 215 x 0.8 mm PCB antenna, an 85 x 55 mm ISO15693 card reached 350 mm in the reference test.
The comparison below uses 85 x 55 mm cards. All distances are in mm. Antennas other than the included 52 x 5.5 mm FPC antenna are sold separately.
| Antenna | MIFARE S50 | ISO15693 | ISO14443B |
|---|---|---|---|
| 52 x 5.5 mm FPC (included) | 45 | 30 | 65 |
| 50 x 40 mm FPC | 105 | 140 | 50 |
| 40 x 20 mm FPC | 40 | 55 | 5 |
| 25 x 10 mm FPC | 5 | 20 | 12 |
| 27 mm diameter FPC | 50 | 32 | 25 |
| 13 mm diameter FPC | 10 | 40 | NC |
| 283 x 187 x 0.8 mm PCB | 130 | 190 | NC |
| 311 x 215 x 0.8 mm PCB | 230 | 350 | 15* |
*15 mm is read-only; writing failed. Other numerical results are read/write distances. NC means no valid read/write distance was recorded, and does not mean zero.
All six FPC antennas in this comparison had anti-metal backing film. Both PCB antennas were tested without backing film. Range varies with the antenna, tag, cable and installation; these reference measurements are not a guaranteed distance for every application. See the datasheet for results with all six tested card and tag types.
Package contents
- 1 x ST25R3916B Mini V2 NFC reader module
- 1 x 52 x 5.5 mm FPC antenna with anti-metal backing film
