Abstract:
A semiconductor device includes: a first cell; a second cell; a first match line and a second match line; a first search line pair, first data being transmitted through the first search line pair; a second search line pair, second data being transmitted through the second search line pair; a first logical operation cell connected to the first search line pair and the first match line, and configured to drive the first match line based on a result of comparison between information held by the first and second cells and the first data; and a second logical operation cell connected to the second search line pair and the second match line, and configured to drive the second match line based on a result of comparison between information held by the first and second cells and the second data.
Abstract:
In an image information chip or the like, a multi-port SRAM is embedded with a logic circuit. When the 3 port is used, the 1 port may serve as a differential write and readout port, and the 2 port may serve as a single ended readout dedicated port. While the occupied area of an embedded SRAM can be reduced, the number of write and readout ports is limited to only one, and readout characteristics as fast as differential readout cannot be expected in single ended readout. A new arrangement is therefore provided in which three differential write and readout ports are included in a memory cell structure of the embedded SRAM, an N-well region, for example, is arranged at the center of a cell, and a P-well region is arranged on both sides thereof.
Abstract:
In an image information chip or the like, a multi-port SRAM is embedded with a logic circuit. When the 3 port is used, the 1 port may serve as a differential write and readout port, and the 2 port may serve as a single ended readout dedicated port. While the occupied area of an embedded SRAM can be reduced, the number of write and readout ports is limited to only one, and readout characteristics as fast as differential readout cannot be expected in single ended readout. A new arrangement is therefore provided in which three differential write and readout ports are included in a memory cell structure of the embedded SRAM, an N-well region, for example, is arranged at the center of a cell, and a P-well region is arranged on both sides thereof.
Abstract:
In a semiconductor memory device, static memory cells are arranged in rows and columns, word lines correspond to respective memory cell rows, and word line drivers drive correspond to word lines. Cell power supply lines correspond to respective memory cell columns and are coupled to cell power supply nodes of a memory cell in a corresponding column. Down power supply lines are arranged corresponding to respective memory cell columns, maintained at ground voltage in data reading and rendered electrically floating in data writing. Write assist elements are arranged corresponding to the cell power supply lines, and according to a write column instruction signal for stopping supply of a cell power supply voltage to the cell power supply line in a selected column, and for coupling the cell power supply line arranged corresponding to the selected column at least to the down power supply line on the corresponding column.
Abstract:
A semiconductor device avoids the disturb problem and the collision between write and read operations in a DP-SRAM cell or a 2P-SRAM cell. The semiconductor device 1 includes a write word line WLA and a read word line WLB each coupled to memory cells 3. A read operation activates the read word line WLB corresponding to the selected memory cell 3. A write operation activates the write word line WLA corresponding to the selected memory cell 3. The selected write word line WLA is activated after activation of the selected read word line WLB in an operation cycle that performs both read and write operations.
Abstract:
A semiconductor device includes: a first cell; a second cell; a first match line and a second match line; a first search line pair, first data being transmitted through the first search line pair; a second search line pair, second data being transmitted through the second search line pair; a first logical operation cell connected to the first search line pair and the first match line, and configured to drive the first match line based on a result of comparison between information held by the first and second cells and the first data; and a second logical operation cell connected to the second search line pair and the second match line, and configured to drive the second match line based on a result of comparison between information held by the first and second cells and the second data.
Abstract:
A semiconductor device is provided where high-speed search operation can be performed. The semiconductor device includes a plurality of search memory cells arranged in a matrix form a plurality of search line pairs which are respectively provided corresponding to memory cell columns and which respectively transmit a plurality of search data to be compared with data stored in the search memory cells, a plurality of search drivers which are respectively arranged at corresponding to one end sides of the search line pairs and which drive the search line pairs according to the search data, and a plurality of assist circuits which are respectively provided corresponding to the other end sides of the search line pairs and which assist driving corresponding search line pairs according to the search data.
Abstract:
Cell power supply lines are arranged for memory cell columns, and adjust impedances or voltage levels of the cell power supply lines according to the voltage levels of bit lines in the corresponding columns, respectively. In the data write operation, the cell power supply line is forced into a floating state according to the bit line potential on a selected column and has the voltage level changed, and a latching capability of a selected memory cell is reduced to write data fast. Even with a low power supply voltage, a static semiconductor memory device that can stably perform write and read of data is implemented.
Abstract:
In an image information chip or the like, a multi-port SRAM is embedded with a logic circuit. When the 3 port is used, the 1 port may serve as a differential write and readout port, and the 2 port may serve as a single ended readout dedicated port. While the occupied area of an embedded SRAM can be reduced, the number of write and readout ports is limited to only one, and readout characteristics as fast as differential readout cannot be expected in single ended readout. A new arrangement is therefore provided in which three differential write and readout ports are included in a memory cell structure of the embedded SRAM, an N-well region, for example, is arranged at the center of a cell, and a P-well region is arranged on both sides thereof.
Abstract:
Cell power supply lines are arranged for memory cell columns, and adjust impedances or voltage levels of the cell power supply lines according to the voltage levels of bit lines in the corresponding columns, respectively. In the data write operation, the cell power supply line is forced into a floating state according to the bit line potential on a selected column and has the voltage level changed, and a latching capability of a selected memory cell is reduced to write data fast. Even with a low power supply voltage, a static semiconductor memory device that can stably perform write and read of data is implemented.