Abstract: A control signal generator to generate control signals for a readout integrated circuit (ROIC) includes a content addressable memory (CAM) and a random access memory (RAM). The CAM may have data stored within it that is indicative of times at which control signal switching events are to occur during generation of the control signals. The RAM may have data stored within it that is indicative of particular control signals that are to be toggled at the times indicated within the CAM.

Abstract: A multi-wafer CAM cell in which the negative effects of increased travel distance have been substantially reduced is provided. The multi-wafer CAM cell is achieved in the present invention by utilizing three-dimensional integration in which multiple active circuit layers are vertically stack and vertically aligned interconnects are employed to connect a device from one of the stacked layers to another device in another stack layer. By vertically stacking multiple active circuit layers with vertically aligned interconnects, each compare port of the inventive CAM cell can be implemented on a separate layer above or below the primary data storage cell. This allows the multi-wafer CAM structure to be implemented within the same area footprint as a standard Random Access Memory (RAM) cell, minimizing data access and match compare delays.

Abstract: A word line driver circuit for providing a suppressed word line voltage includes a switch configured to selectively load a word line to a suppressed word line voltage node and a word line charging circuit coupled between a high power supply node and the suppressed word line voltage node. The word line charging circuit includes a first transistor device responsive to a control pulse for charging the suppressed word line voltage node to a suppressed word line voltage and a second transistor device for maintaining the suppressed word line voltage.

Abstract: A memory structure and method to fabricate the same is described. The memory structure includes a first memory cell having a first pair of non-volatile portions. The memory structure also includes a second memory cell having a second pair of non-volatile portions. The first and second pairs of non-volatile portions are disposed in an inter-locking arrangement.

Abstract: Integrated circuits may include configurable-port memory cells. The configurable-port memory cells may be operable in single-port mode and multiport mode. Each configurable-port memory cell may be coupled to first and second pairs of data lines. The configurable-port memory cell may include a first latching circuit having a first data storage node and a second latching circuit having a second data storage node. The first latching circuit may be coupled to the first pair of data lines through a first set of access transistors, whereas the second latching circuit may be coupled to the second pair of data lines through a second set of access transistors. An additional transistor may be coupled between the first and second data storage nodes. The configurable-port memory cell is configured in the single-port mode if the additional transistor is turned off and is configured in the dual-port mode if the additional transistor is turned on.

Abstract: According to one embodiment, a system for retaining M bits of state data of an integrated circuit during power down includes M serially coupled scan flip flops divided into M/N groups, where the M scan flip flops are able to save/restore the M bits of state data. Each group contains a merged scan flip flop coupled to a series of scan flip flops. The merged scan flip flop in each of the groups is coupled to a respective read port of a memory unit, and a final scan flip flop in each of the groups is coupled to a respective write port of the memory unit. The system enables the memory unit to save the M bits of state data in N clock cycles. Each merged scan flip flop has a read select input that enables restoring of the state data into the M scan flip flops in N clock cycles.

Abstract: A ternary content addressable memory (TCAM) is formed by TCAM cells that are arranged in an array. Each TCAM cell includes a first and second SRAM cells and a comparator. The SRAM cells predominantly in use have a horizontal topology with a rectangular perimeter defined by longer and shorter side edges. The match lines for the TCAM extend across the array, and are coupled to TCAM cells along an array column. The bit lines extend across the array, and coupled to TCAM cells along an array row. Each match line is oriented in a first direction (the column direction) that is parallel to the shorter side edge of the horizontal topology layout for the SRAM cells in each CAM cell. Each bit line is oriented in a second direction (the row direction) that is parallel to the longer side edge of the horizontal topology layout for the SRAM cells in each CAM cell.

Abstract: SRAM cells and SRAM cell arrays are described. In one embodiment, an SRAM cell includes a first inverter and a second inverter cross-coupled with the first inverter to form a first data storage node and a complimentary second data storage node for latching a value. The SRAM cell further includes a first pass-gate transistor and a switch transistor. A first source/drain of the first pass-gate transistor is coupled to the first data storage node, and a second source/drain of the first pass-gate transistor is coupled to a first bit line. The first source/drain of the switch transistor is coupled to the gate of the first pass-gate transistor.

Abstract: The present invention provides a content addressable memory capable of higher frequency operation than conventional. When a search enable signal supplied from a search control circuit is asserted, each of search line drivers transfers search data to each CAM cell of a CAM memory array via a search line pair. The search line enable signal is transmitted to the search line drivers via a single control signal line coupled to the search control circuit. The control signal line is coupled to the search line drivers in such a manner that the search line enable signal passes through coupling nodes between the search line drivers and the control signal line in an arrangement order of the search line drivers from the side far away as viewed from match amplifiers.

Abstract: Integrated circuits may include memory elements that are provided with voltage overstress protection. One suitable arrangement of a memory cell may include a latch with two cross-coupled inverters. Each of the two cross-coupled inverters may be coupled between first and second power supply lines and may include a transistor with a gate that is connected to a separate power supply line. Another suitable memory cell arrangement may include three cross-coupled circuits. Two of the three circuits may be powered by a first positive power supply line, while the remaining circuit may be powered by a second positive power supply line. These memory cells may be used to provide an elevated positive static control signal and a lowered ground static control signal to a corresponding pass gate. These memory cells may include access transistors and read buffer circuits that are used during read/write operations.

Abstract: To improve reliability of a semiconductor device having an SRAM. The semiconductor device has a memory cell including six n-channel type transistors and two p-channel type transistors formed over a silicon substrate. Over the silicon substrate, a first p well, a first n well, a second p well, a second n well, and a third p well are arranged in this order when viewed in a row direction. First and second positive-phase access transistors are disposed in the first p well, first and second driver transistors are disposed in the second p well, and first and second negative-phase access transistors are arranged in the third p well.

Abstract: The memory device includes a memory cell unit of the electrically erasable and programmable non-volatile type including two memory cells respectively connected to two bit lines via two bit line select transistors. The common terminal between the bit line select transistor and the floating-gate transistor of each memory cell of the memory cell unit is connected to the control gate of the floating-gate transistor of the other memory cell of the memory cell unit.

Abstract: The invention provides a content-addressable memory cell formed by two transistors that are configured so that one of the transistors is for storing a data bit and the other for is storing the complement of the data bit. Each transistor has a back control gate that can be controlled to block the associated transistor. The device also includes a comparison circuit that is configured to operate the first and second transistors in read mode while controlling the back control gate of each of the transistors so as to block the passing transistor if a proposed bit and the stored bit correspond. Then, the presence or absence of current on a source line linked to the source of each of the transistors indicates whether the proposed bit and the stored bit are identical or not. The invention also provides methods for operating the content-addressable memory cells of this invention, as well as content-addressable memories having a plurality of the content-addressable memory cells of this invention.

Abstract: Static-based comparators and methods for comparing data are disclosed. The static-based comparator is configured to selectively switch at least one comparator output in response to a comparison of corresponding data with compare data, and a validity indicator for the data. If the validity indicator indicates valid data, the static-based comparator switches to drive the comparator output indicating either a match or mismatch between corresponding compared data. If the validity indicator indicates invalid data, the static-based comparator provides a mismatch on the comparator output without switching the static-based comparator regardless of whether or not the data matches the compare data. In this manner, the static-based comparator does not dissipate power switching the comparator output for data marked invalid. The static-based comparator can be employed in content addressable memories (CAMs) for comparing one or more bits of tag data to corresponding bit(s) of compare data.

Abstract: A layout structure of bit line sense amplifiers for use in a semiconductor memory device includes first and second bit line sense amplifiers arranged to share and be electrically controlled by a first column selection line signal, and each including a plurality of transistors. In this layout structure, each of the plurality of transistors forming the first bit line sense amplifier is arranged so as not to share an active region with any transistors forming the second bit line sense amplifier.

Abstract: An apparatus comprising a memory array and a plurality of processing circuits. The memory array may be configured to store a plurality of data bits in a plurality of rows and a plurality of columns. A plurality of data words may be stored in a respective plurality of the columns. The plurality of processing circuits may each be configured to compare (i) a test bit of a plurality of bits of an input data word with (ii) a test bit of one of the plurality of columns to determine a match. The compare may occur on a first clock cycle of an input clock signal. Each of the plurality of processing circuits may be configured to power down a respective column of the memory array if the test bit of the input data word does not match the test bit of the column.

Abstract: A content addressable memory (CAM) device includes an array of memory cells arranged in rows and columns; compare circuitry configured to indicate match results of search data presented to each row of the array; and compare circuitry configured to indicate match results of search data presented to each column of the array, thereby resulting in a two-dimensional search capability of the array.

Abstract: Integrated circuits with memory elements are provided. The memory elements may be arranged in a memory block. The memory block may include cross-coupled inverters that store data. The stored data may be used to program pass transistors. Transistors in the memory block may be stressed. Depending on the type of stress-inducing layer used, a tensile stress or a compressive stress may be built in into the transistors. Stressed transistors may help improve the routing speed of the memory block. Stressed transistors may be implemented using dual gate-oxide process.

Abstract: A content addressable memory and method of operation uses a memory array having a plurality of rows of stored content addressable memory data and compare circuitry for comparing received comparand data with the stored content addressable memory data. A hit signal and one or more parity bits is provided for each row. Erroneous hit detection circuitry coupled to the memory array for each row generates a row error indicator in response to a comparison between parity of the comparand data and parity of a row that is correlated to the hit signal as qualified by assertion of a hit signal of that row. The erroneous hit detection circuitry uses the row error indicator for each row to provide an output which indicates whether at least one asserted hit signal corresponds to an erroneous hit.

Abstract: A storage cell is provided with improved robustness to soft errors. The storage cell comprises complementary lower storage nodes and complementary upper storage nodes. The upper storage nodes act to limit feedback between the lower storage nodes and are capable of restoring the logical state of the core storage nodes in the event of a soft error. Similarly the lower storage nodes act to limit feedback between the upper storage nodes with the same effect. An SRAM cell utilizing the proposed storage cell can be realized with two access transistors configured to selectively couple complementary storage nodes to a corresponding bitline. A flip-flop can be realized with a variety of transfer gates which selectively couple data into the proposed storage cell.

Abstract: A method for producing a configurable content-addressable memory (CAM) cell design, in which the method includes: inputting the configurable CAM cell design to a computer, the configurable CAM cell design capable of being configured as one of a binary CAM design and a ternary CAM design, depending on connections of a metal overlay; selecting one of a first metal overlay design for the binary CAM design and a second metal overlay design for a ternary CAM design; if the first metal overlay design is selected, then combining the first metal overlay design with the configurable CAM cell design to produce a binary CAM design including two binary CAM cells with a single search port, and outputting the binary CAM design; and if the second metal overlay design is selected, then combining the second metal overly design with the configurable CAM cell design to produce a ternary CAM design including a single ternary CAM cell with two search ports, and outputting the ternary CAM design by the computer.

Abstract: Arrays of memory elements may have data lines and address lines. Each memory element may have five transistors. An address decoder may receive an undecoded address signal and may produce a corresponding decoded address signal. The decoded version of the address signal may be used in addressing the memory elements in the memory array. The memory array may be loaded with configuration data. Loaded memory elements may each provide a static output control signal that configures a programmable logic transistor in programmable logic. The memory elements may be powered with an elevated voltage during normal operation. Boosted address signals may be used when addressing the memory array. The address decoder may contain circuitry that is responsive to a clear control signal and an address output enable signal. The memory element array may be cleared by asserting the clear control signal and address output enable signal.

Abstract: A CAM device memory array having different types of memory cells. A CAM device memory array is subdivided into at least two different portions, where each portion uses only one particular type of CAM cell, and each portion is dedicated to storing a particular type of data. In particular, at least one portion consists of binary CAM cells and the other portion consists of ternary CAM cells. The portions can be partitioned along the row, or matchline, direction or along the bitline direction. Since particular data formats only require predefined bit positions of a word of data to be ternary in value, the remaining binary bit positions can be stored in binary CAM cells. Therefore, the CAM device memory array will occupy an overall area that is less than memory arrays of the same density consisting exclusively of ternary CAM cells.

Abstract: A ternary content addressable memory (TCAM) cell circuit formed in a TCAM memory cell array having cells arranged in rows and columns can include a first storage circuit with first and second data path, a second storage circuit with a third and fourth data path, and a compare circuit. No more than four conductive lines in a column wise direction have a direct electrical connection to the TCAM cell. Such conductive lines can include a first bit line coupled to the first data path and the third data path and a second bit line coupled to the second data path and the fourth data path.

Abstract: A memory device is a provided that includes memory cells situated at the intersection of lines and columns, and a dummy path including a first dummy column having two bit lines to which there are connected dummy memory cells, and a circuit adapted to select at least one of the dummy memory cells to discharge one of the dummy bit lines. The dummy path also includes at least one second dummy column adapted to generate a dummy leakage current (representing a leakage current of a column of the memory device selected in read mode), and a circuit adapted to copy the dummy leakage current to the one dummy bit line, so that the discharge of the one dummy bit line also depends on the dummy leakage current.

Abstract: Disclosed herein is a semiconductor memory device including a plurality of memory cells including first and second inverters each having first and second driver transistors and first and second load transistors and including first and second memory node, and first and second transfer transistors. The of the first and second transfer transistors is connected to each of the first and memory nodes respectively. The memory cell is connected to a bit line and complementary bit line via the first and second transfer transistors respectively wherein a supply voltage applied to the bit line and the complementary bit line is lower than a supply voltage applied to the load transistors, and at least a memory-node-side end of a gate insulating film of the first driver transistor, second driver transistor, first load transistor, and the second load transistor have a thickness larger than a thickness of a gate insulating film of the other part.

Abstract: A memory cell includes a first access transistor, first and second pull-up transistors, a depletion transistor, and first and second pull-down transistors. The first access transistor is connected to a word line and connected between a first bit line and a first data node. The first pull-up transistor is connected to a first power supply point and the second pull-up transistor is connected to the first power supply point and the second data node. The first pull-down transistor is connected to a second power supply point and to the first data node and the second pull-down transistor is connected to the depletion transistor and to the second data node. The depletion transistor is connected to the word line and to the second power supply point.

Abstract: Associative memories capable of outputting multiple reference data close to search data are provided. A memory array compares each of the multiple reference data with the search data in parallel and generates multiple comparison current signals representing the result of the comparison. A WLA converts the multiple comparison current signals into voltages. During the first cycle, the WLA detects the lowest voltage among the voltages as Winner and detects the remaining voltages as Loser. After the second cycle, based on feedback signals, the WLA detects all the voltages other than a voltage detected as Winner during the last preceding cycle, and detects the lowest voltage among the detected voltages as Winner and detects the remaining detected voltages as Loser. The WLA repeats these operations k times.

Abstract: According to one embodiment, a system for retaining M bits of state data of an integrated circuit during power down includes M serially coupled scan flip flops divided into M/N groups, where the M scan flip flops are able to save/restore the M bits of state data. Each group contains a merged scan flip flop coupled to a series of scan flip flops. The merged scan flip flop in each of the groups is coupled to a respective read port of a memory unit, and a final scan flip flop in each of the groups is coupled to a respective write port of the memory unit. The system enables the memory unit to save the M bits of state data in N clock cycles. Each merged scan flip flop has a read select input that enables restoring of the state data into the M scan flip flops in N clock cycles.

Abstract: This invention discloses a static random access memory (SRAM) cell array structure which comprises a first and second bit-line coupled to a column of SRAM cells, the first and second bit-lines being substantially parallel to each other and formed by a first metal layer, and a first conductive line being placed between the first and second bit-lines and spanning across the column of SRAM cells without making conductive coupling thereto, the first conductive line being also formed by the first metal layer.

Abstract: A column of ternary content addressable memory (TCAM) cells includes a bit line pair that is twisted at a location at or near the center of the column. Data is written to (and read from) TCAM cells located above the twist location with a first bit line polarity. Data is written to (and read from) TCAM cells located below the twist location with a second bit line polarity, opposite the first bit line polarity. As a result, read leakage currents introduced by TCAM cells storing ‘Don't Care’ values are reduced.

Abstract: A scheme for bit cell designs for ternary content addressable memory for comparing search data with content data is disclosed. In one embodiment, a system for comparing search data with content data stored in a ternary content addressable memory (TCAM) unit, includes a first static logic gate for comparing a first content data with a first search data, and a second static logic gate coupled to the first static logic gate for comparing a second content data with a second search data. The content data comprises the first content data and the second content data and the search data comprises the first search data and the second search data. The first static logic gate forwards a signal for disabling the second static logic gate if the first content data does not match with the first search data.

Abstract: A content addressable memory (CAM) may include a plurality of precharge circuits, each coupled to a group of CAM cells and comprising a first precharge path that is temporarily enabled in response to an activated first control signal, and a second precharge path that is temporarily enabled in response to an activated second control signal and a valid indication that indicates whether or not the corresponding group of CAM cells stores valid data, the valid indication being different than the first and second control signals.

Abstract: A content addressable memory (CAM) device includes an array of memory cells arranged in rows and columns; compare circuitry configured to indicate match results of search data presented to each row of the array; and compare circuitry configured to indicate match results of search data presented to each column of the array, thereby resulting in a two-dimensional search capability of the array.

Abstract: A content addressable memory (CAM) device includes an array of memory cells arranged in rows and columns; compare circuitry configured to indicate match results of search data presented to each row of the array; and compare circuitry configured to indicate match results of search data presented to each column of the array, thereby resulting in a two-dimensional search capability of the array.

Abstract: A CAM column structure includes an interface that drives search data to a plurality of CAM cells via a search line pair. The CAM cells are divided into sections, each section including: a set of CAM cells, a bit line pair coupled to the set of CAM cells, a sense amplifier coupled to the bit line pair, a tri-state read buffer configured to drive read data from the sense amplifier to the search line pair, and a pair of tri-state write buffers configured to drive write data from the search line pair to the bit line pair. In one embodiment, the pair of tri-state write buffers is replaced by a pair of switches that couple the search line pair to the sense amplifier. The search line pair may be segmented by tri-state buffers, which are controlled to drive the search, read and write data along the search line pair.

Abstract: The present invention discloses a butterfly match-line structure and a search method implemented thereby, wherein the parallelism of the match lines is increased to shorten the search time, and a butterfly-type connection is used to reduce the power consumption and achieve the best energy efficiency. Via the butterfly-type connection, information can be reciprocally transmitted between the parallel match lines, which are independent originally. When a miss case occurs, more succeeding memory cells will not be compared but will be turned off. Thereby, the power consumption is reduced. Further, XOR-based conditional keepers are used to reduce the matching time and the power consumption. Besides, such a circuit is also used to shorten the delay time of the butterfly-type connection.

Abstract: A scheme for ultra-low power content addressable memory based on a ripple search is disclosed. In one embodiment, a system for content addressable memory (CAM), includes a storage unit for storing a portion of content data, and a match module for comparing the portion of the content data with a respective portion of search data received by the match module. The match module includes a first static logic gate associated with a first half of the storage unit storing a sub-portion of the portion of the content data, and a second static logic gate associated with a second half of the storage unit. The first static logic gate forwards a signal for disabling the second static logic gate if the sub-portion of the portion of the content data does not match with a respective sub-portion of the portion of the search data.

Abstract: A read operation and a search operation are performed during the same cycle within a CAM system including a CAM array by: (1) forcing a non-matching condition to exist in the row of the CAM array selected for the read operation, (2) comparing the read data value with the search data value outside of the CAM array to determine whether a match exists, and (3) prioritizing the results of the search operation performed within the CAM array and the results of the comparison performed outside of the CAM array to provide a final search result.

Abstract: A layout structure of bit line sense amplifiers for use in a semiconductor memory device includes first and second bit line sense amplifiers arranged to share and be electrically controlled by a first column selection line signal, and each including a plurality of transistors. In this layout structure, each of the plurality of transistors forming the first bit line sense amplifier is arranged so as not to share an active region with any transistors forming the second bit line sense amplifier.

Abstract: A design structure embodied in a machine readable medium used in a design process includes a content addressable memory (CAM) device having an array of memory cells arranged in rows in a word line direction and columns arranged in a bit line direction, and compare circuitry configured to compare data presented to the array with data stored in each row and column of the array, and simultaneously indicate match results on each row and column of the array, thereby resulting in a two-dimensional, matrix-based data comparison operation.

Abstract: A content addressable memory (CAM) device can include a number of match lines, each coupled to a plurality of CAM cells. The CAM device also includes one or more one precharge circuits. Such a precharge circuit can have a first precharge path that couples a match line to a precharge voltage node in response the activation of a first control signal, and a second precharge path that couples the match line to the precharge voltage node in response to the activation of a second control signal. Prior to a compare operation leakage current through the CAM cells can prevented by disabling the precharge paths and isolating the CAM cells from a reference voltage (e.g., ground). The second control signal can be activated after the first control signal in a compare operation.

Abstract: A memory cell includes an access transistor, first and second pull-up transistors, first and second pull-down transistors, and a first search transistor. The access transistor is connected to a first word line and connected between a first bit line and a first data node. The first pull-up transistor is connected to a first power supply point and the first data node, and the second pull-up transistor is connected to the first power supply point and the second data node. The first pull-down transistor is connected to a second power supply point and the first data node, and the second pull-down transistor is connected to the second power supply point and the second data node. The first search transistor is connected to the second data node and includes a source terminal connected to a third power supply point comprising a voltage less than the voltage at the second power supply point.

Abstract: A content addressable memory (CAM) device includes an array of memory cells arranged in rows in a word line direction and columns arranged in a bit line direction, and compare circuitry configured to compare data presented to the array with data stored in each row and column of the array, and simultaneously indicate match results on each row and column of the array, thereby resulting in a two-dimensional, matrix-based data comparison operation.

Abstract: A content addressable memory (CAM) device can include a plurality of CAM cells arranged in rows and columns to form multi-byte words. Each CAM cell can include a comparator circuit and one or more data storing circuits. Each comparator circuit can have one or more charge transfer paths arranged between a match line and a first voltage source node. Each data storing circuit can include a write circuit that provides a controllable impedance path between one or more charge transfer paths and a data storage node of the data storing circuit.

Abstract: For receiving an input data, a pattern data and a data clock signal and outputting a hit signal and an address signal, a content addressable memory is disclosed to include a plurality of content addressable memory units connected in series, each content addressable memory unit being adapted to receive the input data and the data clock signal and to output a comparison result signal, and an encoder coupled to the comparison result signal of each content addressable memory unit and adapted for outputting a hit signal and a memory address signal subject to the comparison result signal received.

Abstract: A segmented ternary content addressable memory (TCAM) search architecture is disclosed. In one embodiment, a TCAM device with a row of TCAM cells includes a first segment of the TCAM cells for determining a match of corresponding search bits of a search string with a first portion of a stored string in the first segment of the TCAM cells, an evaluation module for generating a search enable signal if the match of the corresponding search bits with the first portion of the stored string is determined, and a second segment of the TCAM cells for determining a match of remaining search bits of the search string with a remaining portion of the stored string in response to the search enable signal.

Abstract: A differential non-volatile content addressable memory array has a differential non-volatile content addressable memory cell which uses a pair of non-volatile storage elements. Each of the non-volatile storage elements can be a split-gate floating gate transistor or a stack gate floating gate transistor having a first terminal, a second terminal, a channel therebetween and a floating gate over at least a portion of the channel to control the conduction of electrons in the channel, and a control gate. The floating gate storage transistor can be in one of two states: a first state, such as erase, in which current can flow between the first terminal and the second terminal, and a second state, such as programmed, in which substantially no current flows between the first terminal and the second terminal. A pair of differential compare data lines connects to the control gate of each of the pair of non-volatile floating gate transistors.

Abstract: A semiconductor integrated circuit includes a word line extending along a first direction, a first and a second N-well regions, a P-well region disposed between the first and the second N-well regions, a memory cell having a first, second, third, and fourth PMOS transistors, and a first and second NMOS transistors, the first and the second PMOS transistors disposed in the first N-well region along a second direction which is different from the first direction, the first and the second NMOS transistors disposed in the P-well region, and the third and the fourth PMOS transistors disposed in the second N-well region along the second direction.

Abstract: A static random access memory (SRAM) circuit includes first SRAM cell and a second SRAM cell that are configured to operate in a shared mode and/or an independent mode. In one example, a shared mode includes the sharing of a memory node of a first SRAM cell. In another example, an independent mode includes isolating a first SRAM cell from a second SRAM cell such that they operate independently.