ESD Protection Design for CMOS Integrated Circuits with Mixed-Voltage I/O Interfaces

With consideration on the gate-oxide reliability, the new ESD protection design with ESD bus for 1.2/2.5-V mixed-voltage I/O interfaces is reported by using the new proposed high-voltage-tolerant power-rail electrostatic discharge (ESD) clamp circuit. This proposed power-rail ESD clamp circuit with only 1.2-V low-voltage NMOS/PMOS devices can be operated under the 2.5-V input conditions without suffering the gate-oxide reliability issue. The experimental results in a 0.13-mum CMOS process have confirmed that the proposed power-rail ESD clamp circuit has high human-body-model (HBM) and machine-model (MM) ESD robustness and fast turn-on speed. The proposed power-rail ESD clamp circuit is an excellent ESD protection solution to the mixed-voltage I/O interfaces