Easy RFID with high-integration reader-chip

The AS3990/91 Ultra-High Frequency (UHF) reader chip is an integrated analogue front-end and data-framing system for a 900MHz Radio-Frequency Identification (RFID) reader system.

With its built-in programming options the unit is suitable for a wide range of applications in UHF RFID systems and requires only a standard 8-bit microcontroller with minimal additional components.

The AS3990/91 comprises the EPC Class 1 - Gen2 protocol (ISO 18000-6c) with digital highspeed logic up to the framing level and supports the ISO 18000-6a and ISO 18000-6b protocols with direct-data mode.

The connection to the microcontroller can be either a 4-pin Serial Data Interface (SDI) or alternatively, for high data rates, an 8-bit parallel interface.

Frame management is performed using a 24-byte FIFO, which decreases processor workload as well as ensuring a smooth datastream and correct protocol handling. All lowlevel transmission codecs and CRC generation is done internally. Additional regulators for the RF section suppress disturbances and thus can operate with noisy mains supply.

A 20MHz crystal is used for the reference oscillator. Using this reference, an additional programmable glitch-free clock output can be used to clock the microcontroller. This saves cost and also reduces overall current draw. In addition, by using the integrated power-management modes of power-down, standby and active, it is possible to shut down or reduce the MCU clock to save additional power.

The transmitter generates 20dBm output power into a 50Ω load and is capable of ASKDSB or PR-ASK modulation. The receiver system enables AM and PM demodulation. The receiver also offers an Automatic Gain Control (AGC) option as well as selectable gain and signal-bandwidth to cover all specified frequencies from 40kHz to 640kHz.

 

FEATURES Gen2 protocol reader engine ISO 18000-6c Compact size Low power Easy implementation

APPLICATIONS UHF RFID reader systems Point-of-Sale (POS) equipment Currency readers Toll systems

 

 

austriamicrosystems / AS399x