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:
Mar. 12, 2013
Filed:
Jun. 16, 2011
Fumiyuki Osanai, Tokyo, JP;
Hiroki Fujisawa, Tokyo, JP;
Fumiyuki Osanai, Tokyo, JP;
Hiroki Fujisawa, Tokyo, JP;
Elpida Memory, Inc., Tokyo, JP;
Abstract
A method includes issuing a calibration command and performing a calibration operation in response to the calibration command. The calibration operation includes adjusting an impedance of a first replica buffer with updating a first code, the first replica buffer being substantially identical in circuit configuration to one of pull-up and pull-down circuits included in an output buffer, adjusting impedance of a second replica buffer with updating a second code, the second replica buffer being substantially identical in circuit configuration to the other of the pull-up and pull-down circuits included in the output buffer, controlling a first latch circuit to hold the first code when the impedance of the first replica buffer reaches a first level, and controlling a second latch circuit to hold the second code when the impedance of the second replica buffer reaches a second level.