Multi-function ESD protection circuit for UHF RFID devices in CMOS technology

The design and implementation of an electrostatic discharge protection suitable for UHF RFID devices in CMOS technology is presented. The circuit implements three fundamental functions for the RF interface: power limiting, backscatter modulation and electrostatic discharge protection. Since all functions are achieved by the same MOS device the additional shunt capacitance at the RF inputs is limited. Therefore the maximum reading distance of the RFID device is improved without sacrificing the electrostatic protection level.