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:
May. 06, 2003

Filed:

Mar. 20, 2002
Applicant:
Inventor:

Masayuki Yoshiyama, Chiba, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11C 1/604 ; G11C 7/00 ;
U.S. Cl.
CPC ...
G11C 1/604 ; G11C 7/00 ;
Abstract

In one of a digital circuit and a semiconductor device, each having a scan chain, a clock fed to a clock input terminal of a flipflop forming the scan chain is switched between during a shift mode and during a capture mode. The time interval from the last clock pulse of the clock signal selected during the shift mode to the first clock pulse of the clock signal selected during the capture mode is set to be shorter than the pulse interval (period) between adjacent pulses of the clock signal selected during the shift mode. In this arrangement, a low-speed tester operates at a substantially high speed, permitting scan-path testing to be carried out with low cost involved.


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