Abstract: The present invention describes circuitry and a method of providing a low power WRITE mode of operation for an integrated circuit comprising an SRAM memory to provide a reduced IDDQ relative to the IDDQ of a full active mode. In one aspect, the circuitry includes an SRAM memory array, mode control circuitry coupled to the array and configured to alter a supply voltage level to the SRAM array based on a mode of operation. The circuitry also includes control inputs coupled to the mode control circuitry for selecting one of the low power write mode, the full active mode, and optionally a retention mode of operation. The mode control circuitry is configured to receive the control inputs to select one of the three modes of operation, and to alter one or more supply voltage levels to the array, for example, the Vss supply voltage using a Vss supply circuit and the Vdd supply voltage using a Vdd supply circuit, based on the selected mode of operation.

Abstract: A novel match/mismatch emulation scheme for an addressed location in a CAM system that includes a plurality of CAM blocks. The plurality of CAM blocks are organized into at least one rectangular array having rows each having a plurality of CAM blocks, a group of CAM cells and associated read/write bit lines connecting the group of CAM cells to an addressed search circuit. During debug mode, where the individual array cells do not participate in search, all the cells in the debug column behave the same way to emulate a match/mismatch on all words. The circuit provides a control input to include address evaluation of a debug cell in a row. The circuit also provides simultaneous switching noise analysis on an evaluating row. The resulting CAM cell provides a circuit to test individual rows for defects and noise analysis.

Abstract: A technique that provides width expansion of two CAMs of varying widths by combining match results from two CAMs by integrating the two CAMs. In one embodiment, a synchronizer circuit triggers the operation of an External Priority Encoder module which can be used to cascade two CAMs to form a wider CAM. When the External Priority Encoder module is used with the CAM, the External Priority Encoder module will receive MATCH signals and control signals from individual CAMs residing on either side, and will be triggered by the last arriving signal between two ports associated with two CAMs. In case one of the ports is disabled the External Priority Encoder module relies totally on the control signal from the other port for operation. The synchronizer circuit has the ability to handle mismatches between the CAMs as well as differentiating valid and invalid combinations between the CAMs.

Abstract: A technique that provides width expansion of two CAMs of varying widths by combining match results from two CAMs by integrating the two CAMs. In one embodiment, a synchronizer circuit triggers the operation of an External Priority Encoder module which can be used to cascade two CAMs to form a wider CAM. When the External Priority Encoder module is used with the CAM, the External Priority Encoder module will receive MATCH signals and control signals from individual CAMs residing on either side, and will be triggered by the last arriving signal between two ports associated with two CAMs. In case one of the ports is disabled the External Priority Encoder module relies totally on the control signal from the other port for operation. The synchronizer circuit has the ability to handle mismatches between the CAMs as well as differentiating valid and invalid combinations between the CAMs.

Abstract: A novel match/mismatch emulation scheme for an addressed location in a CAM system that includes a plurality of CAM blocks. The plurality of CAM blocks are organized into at least one rectangular array having rows each having a plurality of CAM blocks, a group of CAM cells and associated read/write bit lines connecting the group of CAM cells to an addressed search circuit. During debug mode, where the individual array cells do not participate in search, all the cells in the debug column behave the same way to emulate a match/mismatch on all words. The circuit provides a control input to include address evaluation of a debug cell in a row. The circuit also provides simultaneous switching noise analysis on an evaluating row. The resulting CAM cell provides a circuit to test individual rows for defects and noise analysis.

Abstract: A dual port memory implemented using a single port memory core. In an embodiment, the access requests from the two ports are processed in a single memory clock cycle. In one implementation, the access request corresponding to the first port is processed in the high logic state of the memory clock cycle, and the access request corresponding to the second port is processed in the low logic state of the memory clock cycle. A single port memory core may provide multiple memory enable signals and corresponding strobe signals, with each combination of memory enable signal and strobe signal facilitating the memory access request from a corresponding port. An alternative embodiment uses the duration of each clock cycle of the memory clock signal more efficiently by starting the second memory access soon after completion of the first memory access (without waiting for the logic low of memory clock signal).

Abstract: The present invention provides a system for reducing row periphery power consumption in a semiconductor memory device, particularly during sleep mode operation. A memory device (100) according to the present invention has a row (106) of memory cells and driver circuitry (102) preceding the row of memory cells. The present invention provides an intervention circuit (114) instantiated within the driver circuitry proximal to the row of memory cells. The intervention circuit is operated to hold the row of memory cells at a desired state, while the driver circuitry (108, 110) preceding the intervention circuit is powered down.

Abstract: A novel array fault testing for a TCAM system that includes a plurality of TCAM blocks that is organized into at least one rectangular array having rows each having a plurality of TCAM blocks, a group of TCAM cells and associated read/write bit lines connecting the group of TCAM cells to write driver and decoding block. The data decode bypass circuit of the TCAM cell provides a raw write feature to detect faults in a full suite of memory related tests. The debug input of the data debug bypass circuit of the TCAM cell when asserted in the test mode enables the TCAM cell to write raw, unencoded data into the array, and when deasserted in the test mode, enables the testing of the TCAM array. The resulting TCAM cell provides exhaustive fault testing thereby detecting and eliminating faults in TCAM.

Abstract: A self-clocking memory device comprises a memory array, a memory input circuit, and a memory control circuit. The memory input circuit is operable to receive an input clock signal and generate a memory operation initiation signal in response thereto, while the memory control circuit is operable to receive the memory operation initiation signal and generate one or more control signals to initiate a memory operation in response thereto. The memory control circuit is further operable to identify completion of the memory operation and generate a cycle ready strobe signal in response thereto. The memory input circuit receives the cycle ready strobe signal as an input and generates a next memory operation initiation signal in response thereto for initiation of a next memory operation.

Abstract: A self-clocking memory device comprises a memory array, a memory input circuit, and a memory control circuit. The memory input circuit is operable to receive an input clock signal and generate a memory operation initiation signal in response thereto, while the memory control circuit is operable to receive the memory operation initiation signal and generate one or more control signals to initiate a memory operation in response thereto. The memory control circuit is further operable to identify completion of the memory operation and generate a cycle ready strobe signal in response thereto. The memory input circuit receives the cycle ready strobe signal as an input and generates a next memory operation initiation signal in response thereto for initiation of a next memory operation.

Abstract: A technique to enhance performance and reduce silicon area for a TCAM system which includes a plurality of CAM blocks that are organized into at least one rectangular array having rows each having a plurality of CAM blocks, a group of TCAM cells and associated read/write bit lines connecting the group of CAM cells to search bit lines. Each TCAM cell in the TCAM architecture includes a pair of memory elements that is connected to a pair of associated compare circuits such that the interconnections between the memory elements and the compare circuits are substantially vertical in active MOS layers and substantially horizontal in the metal layers to facilitate sharing of adjacent cells thereby providing reduced silicon area and a short aspect ratio.

Abstract: The present invention provides a system for reducing row periphery power consumption in a semiconductor memory device, particularly during sleep mode operation. A memory device (100) according to the present invention has a row (106) of memory cells and driver circuitry (102) preceding the row of memory cells. The present invention provides an intervention circuit (114) instantiated within the driver circuitry proximal to the row of memory cells. The intervention circuit is operated to hold the row of memory cells at a desired state, while the driver circuitry (108, 110) preceding the intervention circuit is powered down.

Abstract: An actual sense amplifier senses a signal received on a bit line to generate a bit, and a latch latches the bit at a time point specified by a latch enable signal. A tracking circuit generates the latch enable signal in an appropriate time window. The tracking circuit may contain a dummy sense amplifier implemented similar to the actual sense amplifier and a dummy column from which the actual sense amplifier senses a signal received upon accessing the dummy memory array. The latch enable signal may be generated after the dummy sense amplifier generates a bit representing the sensed signal. The time taken by the dummy sense amplifier to generate the bit depends on the load offered by the dummy memory array. Accordingly, the dummy memory array is designed to offer sufficient load to ensure that the latch enable signal is generated in an appropriate time window.

Abstract: A sense amplifier which senses whether current is present on a bit line, and generates one logical value if current is present and another logical value if current is not present. As the sense amplifier can be implemented to generate such logical values with a current signal of low strength, memory arrays with correspondingly low drive strength can be implemented. As a result, memory systems which consume minimal power and having high density can be provided. In addition, as the sense amplifiers can operate without any reference signals, the implementation of sense amplifiers may be simplified.

Abstract: A self-clocking memory device comprises a memory array, a memory input circuit, and a memory control circuit. The memory input circuit is operable to receive an input clock signal and generate a memory operation initiation signal in response thereto, while the memory control circuit is operable to receive the memory operation initiation signal and generate one or more control signals to initiate a memory operation in response thereto. The memory control circuit is further operable to identify completion of the memory operation and generate a cycle ready strobe signal in response thereto. The memory input circuit receives the cycle ready strobe signal as an input and generates a next memory operation initiation signal in response thereto for initiation of a next memory operation.

Abstract: A method of testing an Integrated Circuit (IC) and an IC test apparatus is provided. In one embodiment, the method of testing includes (1) applying a voltage to the IC that is not a normal operating voltage of the IC and (2) temporarily biasing a well voltage of transistors in the IC allowing screening for the normal operating voltage.

Abstract: An integrated circuit (IC). The integrated circuit comprises an array (14) of data cells arranged in a plurality of rows and a plurality of columns. Each of the data cells comprises an electrically programmable fuse (40), and each electrically programmable fuse comprises a current path for providing a first digital state when the current path is left intact and for providing a second digital state when the current path is destroyed. Each row of the plurality of rows comprises at least one cell reserved for providing a protection indicator for the row, wherein the protection indicator is selected from a set consisting of read protection and write protection. The integrated circuit also comprises control circuitry (12) for selectively destroying the programmable fuse in selected ones of the data cells in a programmation mode. The integrated circuit also comprises control circuitry (12) for reading selected ones of the data cells in a read mode.

Abstract: A sense amplifier that is capable of sensing small differential voltage between two inputs with full voltage range includes a first inverter 305 and 306; a second inverter 307 and 308 cross coupled with the first inverter; a first transmission gate 301 coupled between a reference node REF and an input of the first inverter; a second transmission gate 302 coupled between a data node RD and an input of the second inverter; a pull-up enable switch 303 coupled between a high side voltage source node VDD, and the first and second inverters; and a pull-down enable switch 304 coupled between a low side voltage source node, and the first and second inverters.

Abstract: A sense amplifier that is capable of sensing small differential voltage between two inputs with full voltage range includes a first inverter 305 and 306; a second inverter 307 and 308 cross coupled with the first inverter; a first transmission gate 301 coupled between a reference node REF and an input of the first inverter; a second transmission gate 302 coupled between a data node RD and an input of the second inverter; a pull-up enable switch 303 coupled between a high side voltage source node VDD, and the first and second inverters; and a pull-down enable switch 304 coupled between a low side voltage source node, and the first and second inverters.

Abstract: An integrated circuit (IC). The integrated circuit comprises an array (14) of data cells arranged in a plurality of rows and a plurality of columns. Each of the data cells comprises an electrically programmable fuse (40), and each electrically programmable fuse comprises a current path for providing a first digital state when the current path is left intact and for providing a second digital state when the current path is destroyed. Each row of the plurality of rows comprises at least one cell reserved for providing a protection indicator for the row, wherein the protection indicator is selected from a set consisting of read protection and write protection. The integrated circuit also comprises control circuitry (12) for selectively destroying the programmable fuse in selected ones of the data cells in a programmation mode. The integrated circuit also comprises control circuitry (12) for reading selected ones of the data cells in a read mode.