SEMICONDUCTOR MEMORY DEVICE HAVING IMPROVED REFRESH CHARACTERISTICS
First Claim
1. A semiconductor memory device comprising:
- a memory array including a plurality of memory cells;
a test unit configured to test refresh characteristics of the memory array and generate a first fail address signal;
a storage unit configured to store the first fail address signal; and
a refresh unit configured to perform a refresh operation on the memory array, the refresh unit being configured to receive the first fail address signal from the storage unit, refresh a first memory cell that does not correspond to the first fail address signal according a first period, and refresh a second memory cell that corresponds to the first fail address signal according to a second period that is shorter than the first period.
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Accused Products
Abstract
A semiconductor memory device having improved refresh characteristics includes a memory array including a plurality of memory cells; a test unit configured to test refresh characteristics of the memory array and generate a first fail address signal; a storage unit configured to store the first fail address signal; and a refresh unit configured to perform a refresh operation on the memory array, wherein the refresh unit is configured to receive the first fail address signal from the storage unit, perform the refresh operation on a first memory cell that does not correspond to the first fail address signal according to a first period, and perform the refresh operation on a second memory cell that corresponds to the first fail address signal according to a second period that is shorter than the first period.
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Citations
20 Claims
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1. A semiconductor memory device comprising:
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a memory array including a plurality of memory cells; a test unit configured to test refresh characteristics of the memory array and generate a first fail address signal; a storage unit configured to store the first fail address signal; and a refresh unit configured to perform a refresh operation on the memory array, the refresh unit being configured to receive the first fail address signal from the storage unit, refresh a first memory cell that does not correspond to the first fail address signal according a first period, and refresh a second memory cell that corresponds to the first fail address signal according to a second period that is shorter than the first period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A semiconductor memory device comprising:
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a memory array including a first memory cell and a second memory cell; a storage unit configured to store as a fail address signal a second address signal corresponding to the second memory cell; and a refresh unit configured to perform a refresh operation on the memory array, the refresh unit being configured to receive the fail address signal from the storage unit, not refresh the first memory cell and refresh the second memory cell in a first time section of the refresh operation, and the refresh unit being configured to refresh both the first memory cell and the second memory cell in a second time section of the refresh operation. - View Dependent Claims (13, 14, 15)
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16. A semiconductor memory device comprising:
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a memory cell; a test unit configured to test refresh characteristics of the memory cell to determine whether the memory cell is a good cell or a bad cell; a storage unit configured to store a row address of the memory cell if the memory cell is a bad cell; and a refresh unit configured to perform a refresh operation on the memory cell according to a refresh period, the refresh period being based on whether the memory cell is a good cell or a bad cell. - View Dependent Claims (17, 18, 19, 20)
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Specification