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:
Oct. 01, 2002
Filed:
Mar. 27, 2001
Tatsuya Ohguro, Yokohama, JP;
Yoshiaki Toyoshima, Kashiwa, JP;
Kabushiki Kaisha Toshiba, Kanagawa-ken, JP;
Abstract
A semiconductor device with digital and analog circuits has a structure for preventing noise penetration from the digital circuit to the analog circuit. The semiconductor device has a semiconductor substrate, first and second wells independently formed at a surface of the semiconductor substrate, the digital circuit formed at a surface of the first well, and the analog circuit formed at a surface of the second well. The specific resistance of the semiconductor substrate is at least 1000 times as large as the specific resistance of the first well. A conductive guard-ring may be formed in the surface of an area that is between the digital circuit and the second well or between the first well and the second well.