ST25R3914 ST25R3915 Automotive high performance HF reader / NFC initiator with 1 W output power supporting AAT Datasheet - production data Description The ST25R3914/5 are highly integrated NFC Initiators / HF Reader ICs for automotive applications, AEC-Q100 grade 1 qualified, including the analog front end (AFE) and a highly integrated data framing system for ISO 18092 QFN32 / VFQFPN32 (NFCIP-1) initiator, ISO 18092 (NFCIP-1) active target, ISO 14443A and B reader (including high bit rates), ISO 15693 reader and FeliCa reader. Features Implementation of other standard and custom AEC-Q100 qualified protocols like MIFARE Classic is possible using the AFE and implementing framing in the external ISO 18092 (NFCIP-1) Active P2P microcontroller (Stream and Transparent modes). ISO14443A, ISO14443B, ISO15693 and The ST25R3914/5 are positioned perfectly for the FeliCa infrastructure side of the NFC system, where Support HBR up to 848 kbit/s PICC to PCD and users need optimal RF performance and flexibility PCD to PICC framing combined with low power. Capacitive sensing - Wake-up Thanks to automatic antenna tuning (AAT) Automatic antenna tuning system providing technology, the devices are optimized for tuning of antenna LC tank (ST25R3914 only) applications with directly driven antennas. The Automatic modulation index adjustment ST25R3914/5 are alone in the domain of HF reader ICs as they contain two differential low AM and PM demodulator channels with impedance (1 Ohm) antenna drivers. automatic selection The ST25R3914/5 include several features that Up to 1 W in case of differential output make them very suited for low power applications. User selectable and automatic gain control They contain a low power capacitive sensor that Transparent and Stream modes to implement can be used to detect the presence of a card MIFARE Classic compliant or other custom without switching on the reader field. The protocols presence of a card can also be detected by performing a measurement of amplitude or phase Possibility of driving two antennas in single of signal on antenna LC tank, and comparing it to ended mode the stored reference. They also contain a low Oscillator input capable of operating with 13.56 power RC oscillator and wake-up timer that can or 27.12 MHz crystal with fast start-up be used to wake up the system after a defined 6 Mbit/s SPI with 96 bytes FIFO time period, and to check for the presence of a tag using one or more low power detection Wide supply voltage range from 2.4 to 5.5 V techniques (capacitive, phase or amplitude). Wide temperature range: -40 C to 125 C The ST25R3914/5 are designed to operate from a ST25R3914: VFQFPN32, 5 mm x 5 mm wide (2.4 to 5.5 V) power supply range peripheral package with wettable flanks interface IO pins support power supply range ST25R3915: QFN32, 5 mm x 5 mm package from 1.65 to 5.5 V. November 2021 DS11837 Rev 6 1/130 This is information on a product in full production. www.st.comContents ST25R3914/5 Contents 1 Functional overview . 9 1.1 Block diagram . 9 1.1.1 Transmitter . 10 1.1.2 Receiver . 10 1.1.3 Phase and amplitude detector 10 1.1.4 A/D converter . 10 1.1.5 External field detector 10 1.1.6 Quartz crystal oscillator . 11 1.1.7 Power supply regulators 11 1.1.8 POR and bias 11 1.1.9 RC oscillator and wake-up timer 11 1.1.10 ISO-14443 and NFCIP-1 framing . 11 1.1.11 FIFO 12 1.1.12 Control logic 12 1.1.13 SPI . 12 1.2 Application information . 12 1.2.1 Operating modes 13 1.2.2 Transmitter . 14 1.2.3 Receiver . 15 1.2.4 Wake-Up mode . 20 1.2.5 Quartz crystal oscillator . 22 1.2.6 Timers 22 1.2.7 A/D converter . 24 1.2.8 Phase and amplitude detector 24 1.2.9 External field detector 26 1.2.10 Power supply system . 27 1.2.11 Communication with an external microcontroller 29 1.2.12 Direct commands 39 1.2.13 Start timers 48 1.2.14 Test access 48 1.2.15 Power-up sequence 49 1.2.16 Reader operation 49 1.2.17 FeliCa reader mode 54 1.2.18 NFCIP-1 operation . 55 2/130 DS11837 Rev 6