5.5-V I/O in a 2.5-V 0.25-μm CMOS technology
A robust high-voltage-tolerant I/O that does not need process options is presented, demonstrated on 5.5-V-tolerant I/O in a 2.5-V 0.25-/spl mu/m CMOS technology. Circuit techniques limit oxide stress and hot-carrier degradation. Measurements on realized circuits, under accelerated stress conditions, indicate an extrapolated lifetime of hundreds of years for 5.5-V pad voltage swing, 2.2-V supply voltage. The shown concepts can easily be scaled toward newer processes or other interfacing voltages.