The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Nov. 25, 2003

Filed:

Aug. 07, 2002
Applicant:
Inventors:

Yi-Hsu Wu, Hsin-Chu, TW;

Hung-Der Su, Kao-Hsiang County, TW;

Jian-Hsing Lee, Hsin-Chu, TW;

Boon-Khim Liew, Hsinchu, TW;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L 2/972 ;
U.S. Cl.
CPC ...
H01L 2/972 ;
Abstract

A new cascaded NMOS transistor output circuit with enhanced ESD protection is achieved. A driver PMOS transistor has the source connected to a voltage supply, the gate connected to the input signal, and the drain connected to the output pad. A dummy PMOS transistor has the source and the gate connected to the voltage supply, and the drain connected to the output pad. A driver NMOS cascaded stack comprises first and second NMOS transistors. The first NMOS transistor has the source connected to ground and the gate connected to the input signal. The second NMOS transistor has the gate connected to the voltage supply, the source connected to the first NMOS transistor drain, and the drain connected to the output pad. A p− implanted region underlies the n+ region of the drain but does not underlie the n+ region of the source. A dummy NMOS cascaded stack comprises third and fourth NMOS transistors. The third NMOS transistor has the gate and the source connected to ground. The fourth NMOS transistor has the gate connected to the voltage supply, the source connected to the third MOS transistor drain, and the drain connected to the output pad. A p− implanted region underlies the n+ region of the drain but does not underlie the n+ region of the source.


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