ESD protection design for IC with power-down-mode operation

A new ESD protection design for IC with power-down operation is proposed. By adding a VDD ESD bus line and diodes into the new ESD protection scheme, the leakage current from I/O pin to VDD power line can be blocked to avoid malfunction under the power-down-mode operating condition. Under normal circuit operating condition, the proposed ESD protection schemes have no leakage path to interfere with the normal circuit functions. Power-rail ESD clamp circuits between the VDD/VSS power lines and VDD ESD bus line are used to achieve whole-chip ESD protection design. From the experimental results, the human-body-model (HBM) ESD level of the new proposed ESD protection schemes can be greater than 7.5kV in a 0.35-μm silicided CMOS process.