ESD Protection for Mixed-Voltage I/O in LowVoltage Thin-Oxide CMOS

An ESD protection design for 1.2V/2.5V mixed-voltage I/O interfaces is discussed. A high-voltage-tolerant power-rail ESD clamp circuit is used; it is realized with low-voltage devices in a 0.13μm CMOS process. The four-mode ESD stresses on the mixed-voltage I/O pad and the whole-chip pin-to-pin ESD protection can be discharged by the proposed ESD protection scheme