7V tristate-capable output buffer implemented in standard 2.5 V CMOS process

This paper describes high-voltage CMOS buffer architecture that uses low-voltage transistors. The voltage capability of the presented architecture is nearly three times larger than the voltage capability of the used MOSFET's. This buffer topology could be used to provide 3.3 V compatibility of 1.2 V and 1.5 V digital ICs implemented in standard CMOS technology. A 7 V circuit-prototype was fabricated in 0.25 μm 2.5 V CMOS technology. Performed measurements demonstrate stress-free operation in both active and high-impedance mode