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:
Sep. 14, 2010
Filed:
Apr. 23, 2008
Tsuneo Abe, Tokyo, JP;
Tsuneo Abe, Tokyo, JP;
Elpida Memory Inc., Tokyo, JP;
Abstract
A semiconductor device has an output impedance adjustment circuit for automatically adjusting an output impedance of an output circuit including transistors connected in parallel. The output impedance adjustment circuit includes: a replica circuit including a circuit portion of the substantially same configuration as the output circuit; a comparator for comparing a magnitude of the output impedance of the replica circuit with a reference resistor and for outputting a comparison result as an internal counter control signal; a switching controller selectively switching between an external counter control signal from outside and the internal counter control signal; and a counter circuit for performing a count operation selectively according to the internal or the external counter control signal and for outputting a count value as an adjustment code which is supplied to the output circuit and the replica circuit so that each transistor is controlled to be on/off based on the adjustment code.