Semiconductor memory device with a noise filter and method of controlling the same
AssigneeKabushiki Kaisha Toshiba
InventorsTomoyuki Hamano, Shigefumi Ishiguro
Life of this patent
Estimating the term…
Abstract
A semiconductor memory device includes a memory cell array, an output buffer circuit and an input buffer circuit. The memory cell array includes a plurality of memory cells holding data. The output buffer circuit outputs data read from the memory cells. The input buffer circuit receives an address signal for the memory cells and includes a noise filter to remove noise. The filter length of the noise filter is variable according to the output capability of the data in the output buffer circuit.
Claims18
A semiconductor memory device comprising:
- a memory cell array which includes a plurality of memory cells holding data;
- an output buffer circuit which outputs data read from the memory cells;
- and
- an input buffer circuit which receives an address signal for the memory cells and includes a noise filter to remove noise, the filter length of the noise filter being variable according to the output capability of the data in the output buffer circuit.
A semiconductor memory device comprising:
- a memory cell array which includes a plurality of memory cells holding data;
- an output buffer circuit which outputs data read from the memory cells;
- an input buffer circuit which receives an address signal for the memory cells and includes a noise filter to remove noise;
- and
- a register which controls a data output characteristic of the output buffer and a filter length of the noise filter on the basis of a control signal externally received.
A method of controlling a semiconductor memory device comprising:
- accepting a first control signal input to the semiconductor memory device after the power supply of the semiconductor memory device has been turned on;
- referring to a table which holds the relationship between the first control signal and the current driving power of a data output circuit and generating a second control signal which controls the data output circuit so as to produce the current driving power corresponding to the first control signal accepted;
- determining the current driving power of the data output circuit according to the second control signal;
- and
- on the basis of the second control signal, determining the filter length of a noise filter in an input buffer accepting an external input signal in such a manner that the filter length is set greater as the current driving power becomes higher.
Dependencies are inferred from the claim text.