Overview and design of mixed-voltage I/O buffers with low-voltage thin-oxide CMOS transistors

Ming-Dou Ker*, Shih Lun Chen, Chia Sheng Tsai

*Corresponding author for this work

    Research output: Contribution to journalReview articlepeer-review

    54 Scopus citations


    Overview on the prior designs of the mixed-voltage I/O buffers is provided in this work. A new 2.5/5-V mixed-voltage I/O buffer realized with only thin gate-oxide devices is proposed. The new proposed mixed-voltage I/O buffer with simpler dynamic n-well bias circuit and gate-tracking circuit can prevent the undesired leakage current paths and the gate-oxide reliability problem, which occur in the conventional CMOS I/O buffer. The new mixed-voltage I/O buffer has been fabricated and verified in a 0.25-μm CMOS process to serve 2.5/5-V I/O interface. Besides, another 2.5/5-V mixed-voltage I/O buffer without the subthreshold leakage problem for high-speed applications is also presented in this work. The speed, power consumption, area, and noise among these mixed-voltage I/O buffers are also compared and discussed. The new proposed mixed-voltage I/O buffers can be easily scaled toward 0.18- μm (or below) CMOS processes to serve other mixed-voltage I/O interfaces, such as 1.8/3.3-V interface.

    Original languageEnglish
    Pages (from-to)1934-1945
    Number of pages12
    JournalIEEE Transactions on Circuits and Systems I: Regular Papers
    Issue number9
    StatePublished - Sep 2006


    • Gate-oxide reliability
    • Gate-tracking circuit
    • Interface
    • Mixed-voltage I/O buffer


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