ESD Protection Design With Diode-Triggered Quad-SCR for Separated Power Domains

Abstract

To effectively protect the interface circuit between separated power domains from electrostatic discharge (ESD) damage, a new diode-triggered quad-silicon-controlled rectifier (DTQSCR) is proposed and realized in a 0.18-mu m 1.8-V/3.3-V CMOS process. Since the DTQSCR embeds four silicon-controlled rectifier paths and a structure of back-to-back diodes, the silicon area can be efficiently reduced more than 30% as compared to the traditional ESD protection design under the same ESD specification. From the measurement results in silicon chip, an interface circuit (level shifter) with the proposed ESD protection design can successfully sustain a human-body-model of greater than 5.5 kV. The proposed ESD protection device is suitable to protect the interface circuits between different power domains.