Patent ID: 6483373
Filing Date: 2002-11-19
Classification: G11C

Abstract:
A semiconductor device having an input line for propagating a signal applied from an input port to an input buffer in the semiconductor device, the semiconductor device comprising two or more signature circuits connected in parallel between the input line and a voltage node, the signature circuits being selectively enabled in response to a control signal,wherein at least one of the two or more signature circuits includes an indexer and a selector connected in series between the voltage node and the input line, wherein two terminals of the selector are electrically short-circuited or opened in response to the control signal, the indexer comprises 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, and a voltage drop in the indexer varies with a combination of the signature fuses which are cut or uncut.