Ultra-low power HF RFID reader IC – RA12

The RA12 is a single-chip reader ASIC for 13.56-MHz RFID/contactless standard protocols. The RA12 supports and compatibles with all major global secured baseband ISO standards including ISO14443 Type A, Type B, Crypto_M cards, and Smartlabel ISO15693. The RA12 provides a hi-speed SPI controller/host interface with a built-in 64-byte FIFO for smooth data transfer. Furthermore, the embedded codec is capable of handling all bit-level coding/encoding, encrypting/decrypting as well as frame-level manipulation for transmission and reception. The chip is well suited for mobile devices due to its low power consumption and low operating voltage from 2.7-3.6 V. The ultra-low power on-chip 3.3V regulators are provided to stabilize the chip’s power, and simultaneously supply the power to the external companion microcontroller up to 150 mA.

The RA12 receiver circuit incorporates a full AGC loop allowing a wide dynamic range of RF input signal levels. The chip’s excellent sensitivity performance enables detection of the input signals with amplitudes as low as 1mVpkpk without distorting the data integrity. The receiver filters can be selected optionally either to a predefined band in accordance with the generic required standard setup, or to an arbitrarily defined combination which gives flexibility to cope with various antenna variations/parameters. The baseband circuits permit the inbound/outbound configuration to accept various forms of customized protocols, incoming to the chip and outgoing to the external RF circuitry in the application specific-design system.

The transmitter is capable of accepting a wide range of operating supply voltages to serve various applications, e.g., 5V for base stations or desktop readers, and 3.3V for handheld devices. The transmission controller is entirely used to support all operation status and requests, including FIFO status full/high/low and Transmission complete flag. The transmitter drivers support a wide range of power supply voltages from 2.7 to 5.5 V. A high drive current up to 250 mA is guaranteed for demanding item-level mid-range reader designs. The dual high-powered transmitters can be flexibly configured in various configurations, e.g. differential driving, single-ended driving, and a mode to drive an external Class-E amplifier for improving the drive strength in the gate antenna setup.

The ultra-low power on-chip 3.3V regulator provides stable supply voltage to external companion microcontroller with capability up to 150 mA.

The RA12 contains efficient power saving modes: hard power down, soft power down, standby and low-power card detection. The low-power card detection mode allows the chip to not operate at full power continuously. The chip periodically senses the external card. If external card is detected, interrupt signal will be sent to MCU to wake up the system.

To facilitate operation of the companion microcontroller, the RA12 is fully equipped with on-chip peripheral support devices such as an RF-trig timer; a host interrupt generator, and a clock divider. The RA12 is offered in a QFN package with excellent heat dissipation when self-mounted on PCB.

Highlight Features

• Low Power Card Detection
• External RF Field Detection
• Support Protocol
  o ISO14443A/B, all bit rates
   106, 212, 424 and 848 kbps
  o ISO15693, all modes
   Downlink 1 of 4 and 1 of 256
   Uplink 6.6 / 13/ 26 / 53 kbps with 1 subcarrier
   Uplink 6.6 / 13/ 26 kbps with 2 sub-carrier
  o NFC Tag Type 1 & PicoTag
  o NFC Bar Code Data Format

Transmitter

• Proximity operating distance up to 10 cm (based on 3×4 cm2 antenna)
• Modulation index adjustable by software
• Output Current up to 250 mA at 5.0 V T_VDD
• Output Impedance 3 Ohms at 5.0 V T_VDD
• Arbitrary modulation by external signal
• Wide operating voltage for Tx from 2.7V to 5.5 V
• On-chip Framing coder for supported standards

Receiver

• Rx sensitivity down to 2 mVp
• On-chip Framing decoder for supported standards
• Automatic Gain Control ( AGC )

Interface and Peripheral

• SPI Interface up to 10 Mbps
• 64-byte send and receive FIFO-buffer
• 64-byte addressing user-configurable registers
• Interrupt (IRQ) PIN
• Programmable timer
• Low jitter on-chip oscillator buffer
• Ultra Low Power On-Chip 3.3V Regulators

Operating Conditions

• Operating temperature from -40°C to 85°C
• Operating Voltage :
  o Receiver A_VDD : 2.7 to 3.6 V
  o Transmitter T_VDD : 2.7 to 5.5 V
  o Digital I/O IO_VDD : 2.7 to 5.5 V
• Power Saving Mode
  • Hard Power Down : 0.5 uA
  • Soft Power Down : 4.7 uA
  • Standby : 1.0 mA
  • Card Detection – Sleep : 4.7 uA

Package

• Small QFN4x4 24-Pin with Heat sink pad.
• Tested sawn wafer.

Applications

• Secure Access Control / Door Lock
• Toy
• Handheld RFID Reader
• Contactless payment system