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. 25, 2005
Filed:
Aug. 28, 2003
Kazuhiro Nakajima, Kanagawa, JP;
Kazuhiro Nakajima, Kanagawa, JP;
NEC Electronics Corporation, Kawasaki, JP;
Abstract
A ring oscillator for a test apparatus and method for verifying fabrication of transistors in an integrated circuit on a die under test is implemented. The ring oscillator is fabricated on the die and includes a positive feedback loop between a circuit output terminal and a feedback input terminal. The feedback loop includes a plurality of delaying stages connected in cascade. A transfer gate is coupled to each delaying stage. Each of the transfer gates includes a pair of transistors of the first and second conductivity types connected in parallel. The ring oscillator is operable to provide a first oscillator output signal during a first test mode when the transistors of the first conductivity type are ON and the transistors of the second conductivity type are OFF. The ring oscillator is operable to provide a second oscillator output signal during a second test mode when the transistors of the first conductivity type are OFF and the transistors of the second conductivity type are ON. The ring oscillator is operable to provide a third oscillator output signal during a third test mode when the transistors of the first conductivity type are ON and the transistors of the second conductivity type are ON.