Dual current data bus clamp circuit of semiconductor memory device
First Claim
1. In a semiconductor memory device comprising a memory cell array for storing data, a row address decoder for decoding row address signals taken in by a row address strobe signal to select memory cells in a row direction of the memory cell array, a column address decoder for decoding column address signals based on a column address decoder enabling signal to select memory cells in a column direction of the memory cell array, conplementary data buses for transmitting data read out from said memory cell array, a data bus pull-up circuit for pulling up said complementary data buses, a data bus clamping circuit for clamping said complementary data buses to a predetermined potential, and a differential amplification type of readout circuit for amplifying on a differential basis data on said complementary data buses to output readout data, said data bus clamping circuit comprising:
- a first discharge circuit for discharging electric charge on said complementary data buses during an active period of the row address strobe signal; and
a second discharge circuit for discharging electric charge on said complementary data buses with a discharge ability larger than said first discharge circuit, during a period of time from the time the active period of the row address strobe signal starts until the column address decoder enabling signal becomes active.
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Accused Products
Abstract
A data bus clamping circuit for use in a semiconductor memory device includes a memory cell array for storing data, a row address decoder for decoding row address signals taken in by a row address strobe signal to select memory cells in a row direction of the memory cell array, a column address decoder for decoding column address signals based on a column address decoder enabling signal to select memory cells in a column direction of the memory cell array, complementary data buses for transmitting data read out from the memory cell array, a data bus pull-up circuit for pulling up the complementary data buses, and a differential amplification type of readout circuit for amplifying on a differential basis data on the complementary data buses to output readout data. The data bus clamping circuit includes a first discharge circuit for discharging electric charge on the complementary data buses during an active period of the row address strobe signal, and a second discharge circuit for discharging electric charge on the complementary data buses with a discharge ability larger than the first discharge circuit, during a period of time from the time the active period of the row address strobe signal starts until the column address decoder enabling signal becomes active.
20 Citations
20 Claims
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1. In a semiconductor memory device comprising a memory cell array for storing data, a row address decoder for decoding row address signals taken in by a row address strobe signal to select memory cells in a row direction of the memory cell array, a column address decoder for decoding column address signals based on a column address decoder enabling signal to select memory cells in a column direction of the memory cell array, conplementary data buses for transmitting data read out from said memory cell array, a data bus pull-up circuit for pulling up said complementary data buses, a data bus clamping circuit for clamping said complementary data buses to a predetermined potential, and a differential amplification type of readout circuit for amplifying on a differential basis data on said complementary data buses to output readout data, said data bus clamping circuit comprising:
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a first discharge circuit for discharging electric charge on said complementary data buses during an active period of the row address strobe signal; and a second discharge circuit for discharging electric charge on said complementary data buses with a discharge ability larger than said first discharge circuit, during a period of time from the time the active period of the row address strobe signal starts until the column address decoder enabling signal becomes active. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 20)
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10. A semiconductor memory device comprising:
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a memory cell array for storing data; a row address decoder for decoding row address signals taken in by a row address strobe signal to select memory cells in a row direction of the memory cell array; a column address decoder for decoding column address signals based on a column address decoder enabling signal to select memory cells in a column direction of the memory cell array; complementary data buses for transmitting data read out from said memory cell array; a data bus pull-up circuit for pulling up said complementary data buses; a data bus clamping circuit for clamping said complementary data buses to a predetermined potential; and a differential amplification type of readout circuit for amplifying on a differential basis data on said complementary data buses to output readout data, said data bus clamping circuit comprising; a first discharge circuit for discharging electric charge on said complementary data buses during an active period of the row address strobe signal; and a second discharge circuit for discharging electric charge on said complemental data buses with a discharge ability larger than said first discharge circuit, during a period of time from the time the active period of the row address strobe signal starts until the column address decoder enabling signal becomes active. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification