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. 21, 2003
Filed:
Jul. 03, 2001
Applicant:
Inventor:
William F. Lawson, Vestal, NY (US);
Assignee:
International Business Machines Corporation, Armonk, NY (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03K 1/9003 ;
U.S. Cl.
CPC ...
H03K 1/9003 ;
Abstract
An output driver impedance calibration circuit which is used to make I/O (input/output) off chip driver characteristics, for a plurality of output driver circuits, alike on the same chip. The output impedance of an input/output driver circuit is calibrated by providing an external target impedance reference (it could be a multiple of the actual target output impedance), multiple devices in the output stage of the I/O driver circuit, a circuit to determine the value of the actual output impedance as compared with its target output impedance and a determination of when to stop the calibration process.