900 MHZ radio‐frequency identification rectifier with optimization and reusing of electro‐static discharges protections in 180 nm digital CMOS technology

Sensitivity and electro‐static discharges (ESD) protection level are crucial parameters for any Ultra High‐Frequency (UHF) power rectifier–harvester designed for radio‐frequency identification (RFID) devices. While sensitivity limits the reading range of the interrogator‐to‐tag communication link, the requirement for an adequate protection against ESD is enforced in commercial devices connected to a printed antenna. Both resistive and capacitive parasitics of the protection circuits severely affect RF performance of the device. In the paper, a rectifier for UHF RFID embedding an ESD protection for 2 kV human‐body discharge model (HBM) level is proposed. The target of a low added parasitic capacitance is achieved by adapting the protection circuit to the RFID rectifier and reusing the ESD clamp for additional functions being mandatory in a UHF RFID front end. The layout of the ESD clamp has been optimized for minimum parasitic resistance without sacrificing the protection level. Two UHF harvesters were implemented in a 180 nm digital complementary metal‐oxide semiconductor (CMOS) technology, featuring a minimum sensitivity of ?15.5 dBm with an ESD protection level of 2 kV HBM. Copyright © 2014 John Wiley & Sons, Ltd.