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:
Nov. 19, 2002

Filed:

Sep. 27, 2000
Applicant:
Inventors:

Jong-hyoung Lim, Suwon, KR;

Sang-seok Kang, Suwon, KR;

Hyun-seok Lee, Seoul, KR;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01H 3/776 ;
U.S. Cl.
CPC ...
H01H 3/776 ;
Abstract

An input circuit having one or more individual signature circuits connected in parallel between an input line and an voltage node in a semiconductor device and an individual signature circuit are provided. The individual signature circuits are isolated from an input/output port to which a high frequency signal is applied so that the input/output port of the semiconductor device can operate at high speed. The signature circuits are provided for an input/output port to which a relatively low frequency signal is applied. An individual signature circuit includes an indexer and a selector connected in series between the voltage node and the input line. The selector includes two terminals which are electrically short-circuited or snapped in response to a control signal, and the indexer includes one or more voltage reducing devices connected in series between input and output terminals of the indexer and signature fuses each of which is connected in parallel to corresponding one of the voltage reducing devices. Voltage drop in the indexer varies with a combination of the signature fuses which are cut or uncut. By varying a voltage drop of an indexer in each of the individual signature circuits, a number of indexes are obtained to index various kinds of information of a semiconductor device.


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