Thin-oxide devices for high voltage i/o drivers

Abstract

An I / O driver includes a pull-down module and pull-up module. The pull-down module has one or more NMOS transistors serially coupled between ground and an output node. The pull-up module has one or more PMOS transistors serially coupled between a first voltage and the output node. The gates of the PMOS and NMOS transistors are controlled by a set of differential biases for selectively pulling the output node to the first voltage or ground. The differential biases are separately set for each of the transistors so that a voltage difference across each of the transistors does not exceed a predetermined value, thereby preventing the same from damage.

Description

technical field

[0001] The present invention relates to integrated circuit design, and in particular to high voltage I / O (input / output) drivers (I / O drivers) without thick-oxide devices. Background technique

[0002] Semiconductor technology is developing to extremely deep sub-micron geometries of less than 100 nanometers to more efficiently integrate more complex functions into a single chip. Although sub-100nm devices offer more complex functions and higher performance, they are also more expensive.

[0003] It has been observed that when the channel length of a transistor is small enough, the current still exists due to the leakage current even in the standby state. Therefore, the supply voltage must be reduced relatively proportionally to minimize this leakage current. However, the I / O voltage of conventional I / O drivers is still maintained at a high voltage level such as 3.3V or 2.5V to be compatible with existing systems. In the prior art, thick oxide devices are co...

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