Design of 2.5V/5V mixed-voltage CMOS I/O buffer with only thin oxide device and dynamic N-well bias circuit

Abstract

This paper presents a 2.5V/5V mixed-voltage CMOS I/O buffer that does not need a CMOS technology with a dual-oxide option and complex bias circuits. The proposed mixed-voltage I/O buffer with simpler circuit structure can overcome the problems of leakage current and gate-oxide reliability, which occurring in the conventional CMOS I/O buffer. In this work, the new proposed design has been realized in a 0.25-mum CMOS process, but it can be easily scaled toward 0.18-mum or 0.15-mum processes to serve a 1.8V/3.3V mixed-voltage I/O interface.