The MLX90121 is an ISO compliant 13.56MHz RFID transceiver integrated circuit.
The main features include user selectable modulation depth in write mode, whereas single sub-carrier ASK, FSK and PSK modulations are recognized in the read mode.
The receiver is based on a diode envelope detector, followed by an IF filter and amplifier. A logarithmic amplifier is used for single subcarrier ASK detection, ensuring fast and clean data recovery. The limiting output of the log amp is used for FSK and PSK recovery.
The transmitter uses a built in open drain output transistor, which can provide up to 250 miliwatts of RF power to a 50 ohms load with a 5 volts power supply using the recommended matching network. This is suitable for most short to mid range applications. A simplified antenna and matching network can be used, at the expense of a reduced reading range, for example in hand-held reader applications.
The chip is configured with a serial interface. A synchronization signal is available when the majority voting is used.
Digital part contains ASK, FSK (423 / 484kHz)and PSK (847kHz) decoders and a programmable encoder to facilitate data handling with a low cost microcontroller. The encoder can be programmed with 6 different patterns.
The chip can also be used as an analog frontend, in direct mode.
