Non-volatile memory string module with buffer and method
View Patent ↗During first portion of a first read cycle determining that a first input of a sense amplifier is to receive information based upon a state of a storage cell during a first portion of a read cycle, and determining that a conductance at the first input is substantially equal to a conductance at a second input of the sense amplifier during the first portion. A plurality of NAND string modules are connected to a global bit line of a memory device that includes a memory column where a plurality of NAND strings and a buffer are formed.
1. A device comprising:
a sense amplifier comprising a first input and a second input;
a global bit line to communicate information to the first input of the sense amplifier; and
a plurality of NAND string modules, each one of the plurality of NAND string modules respectively comprising the following corresponding elements:
a first node to communicate information to the global bit line,
a buffer,
a first switch comprising a control node, a first data electrode coupled to an output of the buffer, and a second data electrode, the first switch being operable to communicate information between the first data electrode and the second data electrode in response to an asserted read signal at the control node during a read access;
a plurality of data paths, each data path of the plurality of data paths respectively comprising
the first node,
a corresponding NAND string of a plurality of NAND strings, and
the buffer connected in series between the corresponding NAND string and the first node to communicate information between the corresponding NAND string and the first node,
wherein a first data path of the plurality of data paths comprises the first node, the buffer, and a first NAND string of the plurality of NAND strings, and a second data path of the plurality of data paths comprises the first node, the buffer, and a second NAND string of the plurality of NAND strings.
2. The device of claim 1 , wherein the buffer includes a first portion of an active region and the first NAND string includes a second portion of the active region.
3. The device of claim 1 , wherein the buffer is an open drain buffer.
4. The device of claim 1 , wherein each one of the plurality of NAND string modules further respectively comprises:
a second switch comprising a control node, a first data electrode coupled to the input of the buffer, and a second data electrode, the second switch being operable to communicate information between the first data electrode and the second data electrode in response to an asserted write signal at the control node during a write access.
5. The device of claim 1 , wherein each one of the plurality of NAND string modules further respectively comprises:
a first transistor comprising a control input electrically connected to a second node, a first current electrode, and a second current electrode, wherein information at the output of the buffer is to be communicated to the first node via the first and second current electrodes of the first transistor.
6. The device of claim 5 , wherein each one of the plurality of NAND string modules further respectively comprises:
a second transistor comprising a control input electrically connected to a third node, a first current electrode, and a second current electrode, information at the input of the buffer to be communicated to the first node via the first and second current electrodes of the second transistor.
7. The device of claim 1 further comprising:
a resistive device comprising a first current electrode electrically connected to the control input of the buffer, and a second electrode electrically coupled to a reference node, the reference node operable to provide a reference signal.
8. The device of claim 7 , wherein the resistive device includes a first portion of an active region and the NAND string includes a second portion of the active region.
9. A device comprising:
a sense amplifier comprising a first input and a second input;
a global bit line to communicate information to the first input of the sense amplifier; and
a plurality of NAND string modules each one of the plurality of NAND string modules respectively comprising the following corresponding elements
a node electrically connected to the global bit line,
and
a buffer to communicate information between the NAND string and the node; and
a first switch comprising a control node, a first data electrode coupled to an output of the buffer, and a second data electrode, the first switch being operable to communicate information between the first data electrode and the second data electrode in response to an asserted read signal at the control node during a read access.
10. The device of claim 9 , wherein the buffer is an open drain buffer connected in series between the NAND string and the node to communicate information between the NAND string and the node during a read operation.
11. The device of claim 9 wherein the buffer is to communicate the information between the NAND string and the node during a first read operation, and to communicate bias information between a bias reference node and the node during a second read operation.
12. A method comprising:
selecting a first NAND string of a first plurality of NAND strings of a first NAND string module, the first NAND string module comprising a second plurality of NAND strings and an output, the output electrically connected to a first global bit line associated with a sense amplifier; and
communicating information at a bit line of the first NAND string to the output of the first NAND string module via a buffer and a switch coupled to the buffer in response to the first NAND string being selected and in response to an asserted read signal selecting the switch.
13. The method of claim 12 , wherein the communicating the information is during a first read operation and further comprising:
selecting a second NAND string of the first plurality of NAND strings
subsequent to selecting the first NAND string; and
communicating information at a bit line of the second NAND string to the output of the NAND string module via the buffer and the switch in response to the second NAND string being selected during a second read operation and in response to an asserted read signal selecting the switch, where information at the bit line of the first NAND string is not communicated to the output of the NAND string module via the buffer when information at the bit line of the second NAND string is being communicated via the buffer.
14. The method of claim 13 , further comprising:
selecting a third NAND string of the second plurality of NAND strings subsequent to selecting the first NAND string; and
communicating information at a bit line of the third NAND string to the output of the first NAND string module via the buffer and the switch in response to the third NAND string being selected, where information at the bit line of the first NAND string is not communicated to the output of the NAND string module via the buffer when information at the bit line of the first or second NAND string is being communicated via the buffer.
15. The method of claim 14 , wherein the buffer is between the first plurality of NAND strings and the second plurality of NAND strings.
16. The method of claim 15 , wherein the first plurality of NAND strings and the second plurality of NAND strings comprise all of the NAND strings of the first NAND string module.
17. The method of claim 14 wherein:
communicating information at the bit line of the first NAND string to the output of the first NAND string module further comprises communicating the information at the bit line of the first NAND string to the output of the first NAND string module via a first multiplexer; and
communicating information at the bit line of the third NAND string of the second plurality of NAND strings to the output of the NAND string module further comprises communicating the information at the bit line of the second NAND string to the output of the first NAND string module via a second multiplexer.
18. The method of claim 13 wherein:
communicating information at the bit line of the first NAND string to the output of the first NAND string module further comprises communicating the information at the bit line of the first NAND string to the output of the first NAND string module via a first multiplexer; and
communicating information at the bit line of the second NAND string to the output of the NAND string module further comprises communicating the information at the bit line of the second NAND string to the output of the first NAND string module via the first multiplexer.
19. The method of claim 12 , wherein selecting the first NAND string is in response to the first NAND string being selected during a read cycle, and information is not communicated between the bit line of the first NAND string and the output of the NAND string module via the buffer during a write cycle.
20. The method of claim 12 , further comprising:
biasing, during a read cycle of a NAND storage cell of the first NAND string, a second global bit line to a reference signal in response to selecting the first NAND string, the reference signal having a value independent of storage state of the NAND storage cell;
providing a first logic value to an output node during the read cycle in response to the reference signal when the NAND storage cell has a first storage state; and
providing a second logic value to the output node during the read access based upon the reference signal when the NAND storage cell has a second storage state.