Near-field Communication (nfc) Transceiver Analog Front-end Circuit Design

In recent years, the mobile Internet is developing rapidly, and the smart phone, as a representative of the mobile devices, become people’s more and more important information terminals. NFC(Near Field Communication), which is a kind of close wireless communication technology, can provide the rapid secure communication between devices, and is compatible with the existing RFID technology and easy to extend. The NFC application based on mobile phones, has the broad prospect and a huge market.In order to realize a low power consumption and low cost NFC transceiver analog front-end circuit which is suitable for mobile phone application, this thesis provides a reasonable specification upon the analysis of NFC protocols. The off-chip antenna, the on-chip transmitter and receiver design schemes are given respectively. Finally the simulations are finished with the3.3V device models of SMIC0.18μm EEPROM process.The off-chip antenna is realized in single-ended structure, including EMC filter, direct impedance matching network and antenna coil. The transmitter achieves10%and100%ASK modulation with class D power amplifier. In typical condition the antenna coil oscillates out82.5mA peak current,12.8V peak voltage and1.5～5A/m magnetic field strength. The load-modulated signal amplitude is more than200mV. In receiver link, the4.35to several hundred mV ASK signal, passes through envelope detector, HPF, LPF and amplifier, Schmitt trigger, then becomes baseband data. The receiver sensitivity is4mV(in the load-modulation), the demodulation error rate is less than18%. In typical condition the power consumption of the receiver is8.4μA*3.3V. The working distance of the transceiver is within3cm. The transceiver performance accords with the NFCIP-1(ISO18092) protocol, and also supports all the operating modes of the NFCIP-2(ISO21481) protocol.