Methods, devices, and systems are disclosed that generally perform a time delay determination of a voltage change on a signal node to determine a corresponding signal value on another node causing the voltage change. In an example the circuit device includes a first circuit configured to couple, when enabled, a signal value onto a first node, and a read circuit having an input coupled to the first node. The read circuit is configured to effect a voltage transition of a signal node at a variable rate corresponding to the voltage of the first node, and to determine the signal value based upon a time-to-transition measurement of the signal node.

A method of operating a tracking circuit of a memory device includes charging a node of the tracking circuit to a first predetermined voltage level, the first node being electrically coupled with a first load device. A first plurality of tracking cell transistors are activated to discharge the first node toward a second predetermined voltage level. A reset signal is generated based on a signal at the first node. The reset signal may correspond to a waiting period for reading a memory cell of the memory device.

The present disclosure describes a memory device comprising memory cells at cross points of access lines of a memory array, and a two-transistor driver comprising a P-type transistor and a N-type transistor connected to the P-type transistor, the two-transistor driver being configured to drive a first one of the access lines to a read/program voltage through the two-transistor driver, during a PULSE phase and drive a second one of the access lines physically adjacent to the first one of the access lines to a shielding voltage through the two-transistor driver, during the PULSE phase.

The present disclosure relates to circuits, systems, and methods of operation for a memory device. In an example, a memory device includes a plurality of memory cells, each memory cell having a variable impedance that varies in accordance with a respective data value stored therein; and a read circuit configured to read the data value stored within a selected memory cell based upon a variable time delay determination of a signal node voltage change corresponding to the variable impedance of the selected memory cell.

A method of operating a tracking circuit of a memory device includes charging a node of the tracking circuit to a first predetermined voltage level, the first node being electrically coupled with a first load device. A first plurality of tracking cell transistors are activated to discharge the first node toward a second predetermined voltage level. A reset signal is generated based on a signal at the first node. The reset signal may correspond to a waiting period for reading a memory cell of the memory device.

An operating method of a memory device including a plurality of memory cells may include: measuring data retention times of at least a portion of the plurality of memory cells; and optimizing a refresh operation on the plurality of memory cells using the measurement result.

According to one embodiment, a semiconductor memory device includes a memory cell, a sense amplifier, a first transfer transistor, a second transfer transistor, and a controller. The memory cell can store a first value and a second value. The sense amplifier amplifies the first value or the second value read from the memory cell to the sense node. The first transfer transistor has a first control terminal connected to the sense node. The second transfer transistor has a second control terminal connected to the sense node. The controller applies a backgate potential to backgate terminals of the first transfer transistor and the second transfer transistor.

Implementations described herein relate to various structures, integrated assemblies, and memory devices. In some implementations, a memory device may include a memory array that includes multiple stacks of vertically stacked memory cells. The memory device may include a transistor positioned above a stack of vertically stacked memory cells of the multiple stacks of vertically stacked memory cells. The transistor may include a channel positioned above the stack of vertically stacked memory cells, a first source/drain region on top of a first portion of the channel, a second source/drain region on top of a second portion of the channel, a gate having a top surface that is lower than a top surface of the first source/drain region and that is lower than a top surface of the second source/drain region, and a gate dielectric that separates the gate from the channel.

A three-dimensional memory array may include a first memory array and a second memory array, stacked above the first. Some memory cells of the first array may be coupled to a first layer selector transistor, while some memory cells of the second array may be coupled to a second layer selector transistor. The first and second layer selector transistor may be coupled to one another and to a peripheral circuit that controls operation of the first and/or second memory arrays. A different layer selector transistor may be used for each row of memory cells of a given memory array and/or for each column of memory cells of a given memory array. Such designs may allow increasing density of memory cells in a memory array having a given footprint area, or, conversely, reducing the footprint area of the memory array with a given memory cell density.

A memory circuit includes a plurality of memory cells and a tracking circuit. Each memory cell of the plurality of memory cells includes a cell transistor corresponding to a predetermined transistor configuration. The tracking circuit includes a first tracking bit line, a first tracking word line, a reference voltage node, and a first plurality of tracking cells. Each tracking cell of the first plurality of tracking cells includes a cell transistor corresponding to the predetermined transistor configuration. The cell transistors of the first plurality of tracking cells are electrically coupled in series between the first tracking bit line and the reference voltage node, and gate terminals of the cell transistors of the first plurality of tracking cells are electrically coupled with the first tracking word line.