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.
Patent No.:
Date of Patent:
Jul. 02, 2002
Filed:
Jun. 09, 1998
Harry N. Gardner, Colorado Springs, CO (US);
Aeroflex UTMC Microelectronic Systems, Inc., Colorado Springs, CO (US);
Abstract
A P-channel transistor is disclosed having P+ source and drain regions formed in a N− well, which is formed in a P− substrate. A third P+ region is provided that functions as a well tie. When the P-channel transistor is used as the pull-up transistor in a CMOS “push-pull” output buffer circuit, the P+ well tie prevents undesired current flow from the bus back to the positive voltage supply. This prevents potential damage to the power supply plane and any additional components connected thereto. In another aspect, the N− well has formed therein both a P+ and N+ well tie. Additional switch circuitry is provided which allows for upper level programmability or selection of either one or both of the two well ties, depending upon the ultimate circuit configuration.