Semiconductor nonvolatile memory device and computer system using the same
First Claim
1. A semiconductor nonvolatile memory device comprising:
- a plurality of word lines;
a plurality of memory cells each of which has a control gate and a floating gate and which stores data as a threshold voltage;
an external data terminal to which data is applied; and
one external supply voltage terminal to which a positive supply voltage is applied,wherein each of said plurality of memory cells is coupled to a corresponding word line of said plurality of word lines, andwherein a read voltage to be applied to a selected word line in a read operation for outputting, through said external data terminal, data of memory cells coupled to said selected word line is higher than 0 V and is lower than said positive supply voltage applied to said one external supply voltage terminal.
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Abstract
A semiconductor nonvolatile memory device including transistors whose threshold voltages can be electrically rewritten (erased, written). A read-selected word line voltage Vrw, lower than the supply voltage Vcc applied from the outside, is applied, and the threshold voltage difference between the higher threshold voltage VthH and the lower threshold voltage VthL in the two states of the nonvolatile memory cells is reduced to bring the higher threshold voltage VthH close to the lower threshold voltage VthL. Moreover, a threshold voltage Vthi in the thermally equilibrium state of the memory cell, corresponding to the two threshold voltages of the two states, is set between the higher threshold voltage VthH and the lower threshold voltage VthL.
15 Citations
33 Claims
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1. A semiconductor nonvolatile memory device comprising:
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a plurality of word lines; a plurality of memory cells each of which has a control gate and a floating gate and which stores data as a threshold voltage; an external data terminal to which data is applied; and one external supply voltage terminal to which a positive supply voltage is applied, wherein each of said plurality of memory cells is coupled to a corresponding word line of said plurality of word lines, and wherein a read voltage to be applied to a selected word line in a read operation for outputting, through said external data terminal, data of memory cells coupled to said selected word line is higher than 0 V and is lower than said positive supply voltage applied to said one external supply voltage terminal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A computer system comprising:
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a semiconductor nonvolatile memory device; and a central processing unit coupled to be in electrical communication with the nonvolatile memory device wherein said semiconductor nonvolatile memory device, includes; a plurality of word lines; a plurality of memory cells each of which has a control gate and a floating gate and which stores data as a threshold voltage; an external data terminal to which data is applied; and one external supply voltage terminal to which a positive supply voltage is applied, wherein each of said plurality of memory cells is coupled to a corresponding word line of said plurality of word lines, and wherein a read voltage to be applied to a selected word line in a read operation for outputting, through said external data terminal, data of memory cells coupled to said selected word line is higher than 0 V and is lower than said positive supply voltage applied to said one external supply voltage terminal.
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11. A semiconductor nonvolatile memory device according to claim 11, wherein said positive supply voltage is +3.3 V.
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12. A semiconductor nonvolatile memory device which comprises:
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one external voltage terminal to which a positive supply voltage is applied; a memory cell array including a plurality of nonvolatile semiconductor memory cells each having a control gate, a floating gate, a drain and a source, and arranged in an array; a plurality of word lines to each of which the control gates of corresponding memory cells of said plurality of memory cells are commonly coupled; a plurality of data lines to each of which the drains of corresponding memory cells of said plurality of memory cells are commonly coupled; and sense latch circuits each of which is coupled to a corresponding data line of said plurality of data lines wherein in a read operation, in which said sense latch circuits store data of memory cells coupled to a selected word line, a read voltage which is applied to said selected word line from said plurality of word lines is lower than said positive supply voltage and is higher than 0 V. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A computer system comprising:
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a semiconductor nonvolatile memory device; and a central processing unit, coupled to be in electrical communication with the nonvolatile memory device, wherein said semiconductor nonvolatile memory device includes; one external supply voltage terminal to which a positive supply voltage is applied, a memory cell array including a plurality of nonvolatile semiconductor memory cells each having a control gate, a floating gate, a drain and a source, and arranged in an array; a plurality of word lines to each of which the control gates of corresponding memory cells of said plurality of memory cells are commonly coupled; a plurality of data lines to each of which the drains of corresponding memory cells of said plurality of memory cells are commonly coupled; and sense latch circuits each of which is coupled to a corresponding data line of said plurality of data lines, wherein in a read operation, in which said sense latch circuits store data of memory cells coupled to a selected word line, a read voltage which is applied to said selected word line is lower than said positive supply voltage and is higher than 0 V. - View Dependent Claims (24)
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25. A semiconductor nonvolatile memory device which comprises:
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one external voltage terminal to which a positive supply voltage is applied; a memory cell array including a plurality of nonvolatile semiconductor memory cells each having a control gate, a floating gate, a drain and a source, and arranged in an array; a plurality of word lines to each of which the control gates of corresponding memory cells of said plurality of memory cells are commonly coupled; a plurality of data lines to each of which the drains of corresponding memory cells of said plurality of memory cells are commonly coupled; and sense latch circuits each of which includes a flip-flop circuit coupled to said one external voltage terminal and each of which is coupled to a corresponding data line of said plurality of data lines, wherein in a read operation, in which said sense latch circuits store data of memory cells coupled to a selected word line, a read voltage which is applied to said selected word line from said plurality of word lines is lower than said positive supply voltage and is higher than 0 V. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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Specification