A memory device that operates at high speed is provided.

The memory device includes first and second memory cells, first and second bit lines, first and second switches, and a sense amplifier. The sense amplifier comprises a first node and a second node. The first memory cell is electrically connected to the first node through the first bit line and the first switch, and the second memory cell is electrically connected to the second node through the second bit line and the second switch. The sense amplifier amplifies the potential difference between the first node and the second node. The first memory cell and the second memory cell include an oxide semiconductor in a channel formation region.

To provide a semiconductor device capable of retaining data for a long period. The semiconductor device includes a memory circuit and a retention circuit. The memory circuit includes a first transistor, and the retention circuit includes a second transistor. The memory circuit is configured to write data by turning on the first transistor and to retain the data by turning off the first transistor. The retention circuit is configured to supply a first potential at which the first transistor is turned off to a back gate of the first transistor by turning on the second transistor and to retain the first potential by turning off the second transistor. Transistors having different electrical characteristics are used as the first transistor and the second transistor.

A low-power storage device is provided. The storage device includes a first transistor, a second transistor, a logic element, and a semiconductor element. The second transistor controls supply of a first signal to a gate of the first transistor. When the potential of a second signal to be input is changed from a first potential into a second potential lower than the first potential, the logic element changes the potential of a first terminal of the first transistor from a third potential lower than the second potential into the first potential after the logic element changes the potential of the first terminal of the first transistor from the second potential into the third potential. The semiconductor element has a function of making a second terminal of the first transistor floating. The first transistor includes a channel formation region in an oxide semiconductor film.

A low-power storage device is provided. The storage device includes a first transistor, a second transistor, a logic element, and a semiconductor element. The second transistor controls supply of a first signal to a gate of the first transistor. When the potential of a second signal to be input is changed from a first potential into a second potential lower than the first potential, the logic element changes the potential of a first terminal of the first transistor from a third potential lower than the second potential into the first potential after the logic element changes the potential of the first terminal of the first transistor from the second potential into the third potential. The semiconductor element has a function of making a second terminal of the first transistor floating. The first transistor includes a channel formation region in an oxide semiconductor film.

The present disclosure includes apparatuses and methods related to compute components formed over an array of storage elements. An example apparatus comprises a base substrate material and an array of memory cells formed over the base substrate material. The array can include a plurality of access transistors comprising a first semiconductor material. A compute component can be formed over and coupled to the array. The compute component can include a plurality of compute transistors comprising a second semiconductor material. The second semiconductor material can have a higher concentration of doping ions than the first semiconductor material.

The present disclosure includes apparatuses and methods related to compute components formed over an array of storage elements. An example apparatus comprises a base substrate material and an array of memory cells formed over the base substrate material. The array can include a plurality of access transistors comprising a first semiconductor material. A compute component can be formed over and coupled to the array. The compute component can include a plurality of compute transistors comprising a second semiconductor material. The second semiconductor material can have a higher concentration of doping ions than the first semiconductor material.

The present disclosure includes apparatuses and methods for cache operations. An example apparatus includes a memory device including a plurality of subarrays of memory cells, where the plurality of subarrays includes a first subset of the respective plurality of subarrays and a second subset of the respective plurality of subarrays. The memory device includes sensing circuitry coupled to the first subset, the sensing circuitry including a sense amplifier and a compute component. The first subset is configured as a cache to perform operations on data moved from the second subset. The apparatus also includes a cache controller configured to direct a first movement of a data value from a subarray in the second subset to a subarray in the first subset.

To provide a semiconductor device which can execute the product-sum operation. The semiconductor device includes a first memory cell, a second memory cell, and an offset circuit. First analog data is stored in the first memory cell, and reference analog data is stored in the second memory cell. The first memory cell and the second memory cell supply a first current and a second current, respectively, when a reference potential is applied as a selection signal. The offset circuit has a function of supplying a third current corresponding to a differential current between the first current and the second current. In the semiconductor device, the first memory and the second memory supply a fourth current and a fifth current, respectively, when a potential corresponding to second analog data is applied as a selection signal. By subtracting the third current from a differential current between the fourth current and the fifth current, a current that depends on the sum of products of the first analog data and the second analog data is obtained.

The present disclosure includes apparatuses and methods related to storing a data value in a sensing circuitry element. An example method comprises sensing a first data value with a sense amplifier of a sensing circuitry element, moving a second data value from a first storage location of a compute component to a second storage location of the compute component, and storing, in the first storage location, a third data value resulting from a logical operation performed on the first data value and the second data value. The logical operation can be performed by logic circuitry of the sensing circuitry element.

Disclosed is a clock converting circuit, which includes a first switch that is connected between a first input node for receiving a second input clock and a first node and operates in response to a first logic state of a first input clock, the second input clock delayed with respect to the first input clock as much as 90 degrees, a second switch that is connected between a second input node for receiving the first input clock and a second node and operates in response to a second logic state of the second input clock, and a third switch that is connected between the second node and a ground node and operates in response to a first logic state of the second input clock opposite to the second logic state of the second input clock.