ZHCS363L August 2011 – March 2017 TRF7970A
PRODUCTION DATA.
The TRF7970A is a high-performance 13.56-MHz HF RFID and NFC transceiver IC composed of an integrated analog front end (AFE) and a built-in data framing engine for ISO/IEC 15693, ISO/IEC 14443 A and B, and FeliCa. This includes data rates up to 848 kbps for ISO/IEC 14443 with all framing and synchronization tasks on board (in default mode). The TRF7970A also supports NFC tag type 1, 2, 3, 4, and 5 operations. This architecture lets the customer build a complete cost-effective yet high-performance multiprotocol 13.56-MHz RFID and NFC system together with a low-cost microcontroller.
Other standards and even custom protocols can be implemented by using either of the direct modes that the device offers. These direct modes (0 and 1) allow the user to fully control the analog front end (AFE) and also gain access to the raw subcarrier data or the unframed but already ISO formatted data and the associated (extracted) clock signal.
The receiver system has a dual input receiver architecture. The receivers also include various automatic and manual gain control options. The received input bandwidth can be selected to cover a broad range of input subcarrier signal options.
The received signal strength from transponders, ambient sources, or internal levels is available through the RSSI register. The receiver output is selectable among a digitized subcarrier signal and any of the integrated subcarrier decoders. The selected subcarrier decoder delivers the data bit stream and the data clock as outputs.
The TRF7970A also includes a receiver framing engine. This receiver framing engine performs the CRC or parity check, removes the EOF and SOF settings, and organizes the data in bytes for ISO/IEC 14443 A and B, ISO/IEC 15693, and FeliCa protocols. Framed data is then accessible to the microcontroller (MCU) through a 127-byte FIFO register.
A parallel or serial interface (SPI) can be used for the communication between the MCU and the TRF7970A reader. When the built-in hardware encoders and decoders are used, transmit and receive functions use a 127-byte FIFO register. For direct transmit or receive functions, the encoders and decoders can be bypassed so that the MCU can process the data in real time. The TRF7970A supports data communication voltage levels from 1.8 V to 5.5 V for the MCU I/O interface. The transmitter has selectable output-power levels of 100 mW (+20 dBm) or 200 mW (+23 dBm) equivalent into a 50-Ω load when using a 5-V supply.
The transmitter supports OOK and ASK modulation with selectable modulation depth. The TRF7970A also includes a data transmission engine that comprises low-level encoding for ISO/IEC 15693, ISO/IEC 14443 A and B, and FeliCa. Included with the transmit data coding is the automatic generation of Start Of Frame (SOF), End Of Frame (EOF), Cyclic Redundancy Check (CRC), and parity bits.
Several integrated voltage regulators ensure a proper power-supply noise rejection for the complete reader system. The built-in programmable auxiliary voltage regulator VDD_X (pin 32), is able to deliver up to 20 mA to supply a microcontroller and additional external circuits within the reader system.