Semiconductor memory device
View Patent ↗A semiconductor memory device includes a sense amplifier, and the sense amplifier includes a bus, first and second latch circuits, and a third transistor. The first latch circuit includes a first transistor connected to the bus, and the second latch circuit includes a second transistor connected to the bus. When data is transmitted from the first latch circuit to the second latch circuit, a third transistor is switched on to precharge the bus by applying a first voltage that is lower than a power source voltage of the first and second latch circuits to a gate of the third transistor. Thereafter, second and third voltages that are lower than the power source voltage are applied to gates of first and second transistors, respectively.
1. A semiconductor memory device comprising:
a memory cell array that includes multiple memory cells that are stacked above a semiconductor substrate; and
a sense amplifier that can retain data read from or to be written to a memory cell, the sense amplifier including a bus that can transmit the data, a first latch circuit that includes a first data retention unit and a first transistor connecting the first data retention unit and the bus, a second latch circuit that includes a second data retention unit and a second transistor connecting the second data retention unit and the bus, and a third transistor, wherein
when the data is transmitted from the first latch circuit to the second latch circuit, the third transistor is switched on to charge the bus to an electric potential lower than a power source voltage of the first and second latch circuits, by applying a first voltage lower than the power source voltage to a gate of the third transistor, and
after precharging the bus, second and third voltages that are lower than the power source voltage, are applied to gates of the first and second transistors, respectively.
2. The semiconductor memory device according to claim 1 ,
wherein the second latch circuit precharges the bus by applying a fourth voltage that is lower than the first voltage to a gate of the second transistor, and
thereafter, the third transistor is switched on to precharge the bus.
3. The semiconductor memory device according to claim 2 , wherein a value of the first voltage is greater than or equal to a value of the second voltage and greater than the value of the third voltage, and the value of the second voltage is greater than or equal to the value of the third voltage.
4. The semiconductor memory device according to claim 1 , wherein a value of the first voltage is less than or equal to a value of the second voltage, and the value of the second voltage is greater than a value of the third voltage.
5. The semiconductor memory device according to claim 1 , wherein the first and second transistors are each an n channel MOS transistor.
6. The semiconductor memory device according to claim 5 , wherein when the data is transmitted from the first latch circuit to the second latch circuit, before precharging the bus, the second data retention unit of the second latch circuit is first reset and then set to a floating state.
7. The semiconductor memory device according to claim 1 , wherein
when the data is transmitted from the first latch circuit to the second latch circuit, the bus is set to a high logic level, and the second data retention unit is set to a floating state with the high logic level,
when the first latch circuit retains a high logic level, the first and second transistors are set to an OFF state, and
when the first latch circuit retains a low logic level, the first and second transistors are set to an ON state, and the bus is discharged.
8. The semiconductor memory device according to claim 1 , wherein
at the time of data reading, the sense amplifier causes the data that is read from the memory cell to be retained in at least one of the first and second latch circuits, and
at the time of data writing, the sense amplifier writes the data retained in at least one of the first and second latch circuits to the memory cell.
9. A semiconductor memory device comprising:
a memory cell array that includes multiple memory cells that are stacked above a semiconductor substrate; and
a sense amplifier that can retain data read from or to be written to a memory cell, the sense amplifier including a bus that can transmit the data, a first latch circuit that includes a first data retention unit and a first transistor connecting the first data retention unit and the bus, and a second latch circuit that includes a second data retention unit and a second transistor connecting the second data retention unit and the bus, wherein
when the data is transmitted from the first latch circuit to the second latch circuit, the second latch circuit precharges the bus to an electric potential lower than a power source voltage of the first and second latch circuits by applying a first voltage lower than the power source voltage to a gate of the second transistor, and
after precharging the bus, second and third voltages that are lower than the power source voltage, are applied to gates of the first and second transistors, respectively.
10. The semiconductor memory device according to claim 9 ,
wherein a value of the first voltage is greater than or equal to a value of the second voltage and greater than a value of the third voltage, and the value of the second voltage is greater than or equal to the value of the third voltage.
11. The semiconductor memory device according to claim 9 , wherein the first and second transistors are each an n channel MOS transistor.
12. The semiconductor memory device according to claim 11 , wherein when the data is transmitted from the first latch circuit to the second latch circuit, before precharging the bus, the second data retention unit of the second latch circuit is first reset and then set to a floating state.
13. The semiconductor memory device according to claim 9 , wherein
when the data is transmitted from the first latch circuit to the second latch circuit, the bus is set to a high logic level, and the second data retention unit is set to a floating state with the high logic level,
when the first latch circuit retains a high logic level, the first and second transistors are set to an OFF state, and
when the first latch circuit retains a low logic level, the first and second transistors are set to an ON state, and the bus is discharged.
14. The semiconductor memory device according to claim 9 , wherein
at the time of data reading, the sense amplifier causes the data that is read from the memory cell to be retained in at least one of the first and second latch circuits, and
at the time of data writing, the sense amplifier writes the data retained in at least one of the first and second latch circuits to the memory cell.
15. A semiconductor memory device comprising:
a memory cell array that includes multiple memory cells that are stacked above a semiconductor substrate; and
a sense amplifier that can retain data read from or to be written to a memory cell, the sense amplifier including a bus that can transmit the data, a first latch circuit that includes a first data retention unit and a first transistor connecting the first data retention unit and the bus, and a second latch circuit that includes a second data retention unit and a second transistor connecting the second data retention unit and the bus, wherein
when the data is transmitted from the first latch circuit to the second latch circuit, first and second voltages that are lower than a power source voltage of the first and second latch circuits are applied to gates of the first and second transistors, respectively, when the bus is at ground voltage.
16. The semiconductor memory device according to claim 15 ,
wherein the first and second transistors are each an n channel MOS transistor.
17. The semiconductor memory device according to claim 15 , wherein
when the data is transmitted from the first latch circuit to the second latch circuit, the bus is set to a high logic level, and the second data retention unit is set to a floating state with the high logic level,
when the first latch circuit retains a high logic level, the first and second transistors are set to an OFF state, and
when the first latch circuit retains a low logic level, the first and second transistors are set to an ON state, and the bus is discharged.
18. The semiconductor memory device according to claim 17 , wherein the high logic level to which the bus is set is lower than the high logic level retained by the first latch circuit.
19. The semiconductor memory device according to claim 15 , wherein
at the time of the data reading, the sense amplifier causes the data that is read from the memory cell to be retained in at least one of the first and second latch circuits, and
at the time of the data writing, the sense amplifier writes the data retained in at least one of the first and second latch circuits to the memory cell.
20. The semiconductor memory device according to claim 15 ,
wherein the first voltage is greater than the second voltage.