Static information storage and retrieval – Read/write circuit – Bad bit
Reexamination Certificate
2005-05-31
2005-05-31
Nguyen, Van Thu (Department: 2824)
Static information storage and retrieval
Read/write circuit
Bad bit
C365S222000, C365S202000
Reexamination Certificate
active
06901014
ABSTRACT:
Circuits and methods that enable screening for defective or weak memory cells in a semiconductor memory device. In one aspect, a semiconductor memory device comprises first and second drivers for a SRAM cell. The first driver is connected between a power supply voltage and the cell, which supplies the power supply voltage into the cell in response to a cell power control signal. The second driver is connected between the power supply signal and the cell, which supplies a voltage lower than the power supply voltage into the cell in response to the cell power down signal. A method for screening for defective or weak cells does not require a time for stabilizing a circuit condition after voltage variation to supply the voltage lower than the power supply voltage from a conventional tester because the cell power down signal activates a driver that causes a supply voltage that is lower than the power supply voltage to be loaded directly to the cell, which results in a reduction of the test time for screening defective cells.
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Cho Uk-Rae
Lee Kwang-Jin
Son Young-Jae
DeRosa, Esq. Frank V.
F. Chau & Associates LLC
Nguyen Dang T
Nguyen Van Thu
Samsung Electronics Co,. Ltd.
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