摘要:
A test structure for characterizing a production static random access memory (SRAM) array. The test structure includes a characterization circuit having multiple memory cell columns connected in series to form a ring configuration. The characterization circuit is fabricated on a wafer substrate in common with and proximate to a production SRAM array. The characterization circuit preferably includes SRAM cells having a circuit topology substantially identical to the circuit topology of memory cells within the production SRAM array. In one embodiment, the test structure is utilized for characterizing a multi-port memory array and includes multiple memory cell columns connected in series to form a ring oscillator characterization circuit. Each cell column in the characterization circuit includes multiple SRAM cells each having a latching node and multiple data path access nodes. Selection control circuitry selectively enables the multiple data path access nodes for the SRAM cells within the characterization circuit.
摘要:
A test structure for characterizing a production static random access memory (SRAM) array. The test structure includes a characterization circuit having multiple memory cell columns connected in series to form a ring configuration. The characterization circuit is fabricated on a wafer substrate in common with and proximate to a production SRAM array. The characterization circuit preferably includes SRAM cells having a circuit topology substantially identical to the circuit topology of memory cells within the production SRAM array. In one embodiment, the test structure is utilized for characterizing a multi-port memory array and includes multiple memory cell columns connected in series to form a ring oscillator characterization circuit. Each cell column in the characterization circuit includes multiple SRAM cells each having a latching node and multiple data path access nodes. Selection control circuitry selectively enables the multiple data path access nodes for the SRAM cells within the characterization circuit.
摘要:
A test structure for characterizing a production static random access memory (SRAM) array. The test structure includes a characterization circuit having multiple memory cell columns connected in series to form a ring configuration. The characterization circuit is fabricated on a wafer substrate in common with and proximate to a production SRAM array. The characterization circuit preferably includes SRAM cells having a circuit topology substantially identical to the circuit topology of memory cells within the production SRAM array. In one embodiment, the test structure is utilized for characterizing a multi-port memory array and includes multiple memory cell columns connected in series to form a ring oscillator characterization circuit. Each cell column in the characterization circuit includes multiple SRAM cells each having a latching node and multiple data path access nodes. Selection control circuitry selectively enables the multiple data path access nodes for the SRAM cells within the characterization circuit.
摘要:
A test structure for characterizing a production static random access memory (SRAM) array. The test structure includes a characterization circuit having multiple memory cell columns connected in series to form a ring configuration. The characterization circuit is fabricated on a wafer substrate in common with and proximate to a production SRAM array. The characterization circuit preferably includes SRAM cells having a circuit topology substantially identical to the circuit topology of memory cells within the production SRAM array. In one embodiment, the test structure is utilized for characterizing a multi-port memory array and includes multiple memory cell columns connected in series to form a ring oscillator characterization circuit. Each cell column in the characterization circuit includes multiple SRAM cells each having a latching node and multiple data path access nodes. Selection control circuitry selectively enables the multiple data path access nodes for the SRAM cells within the characterization circuit.
摘要:
A buffer/driver having large output devices for driving multiple loads is configured with three parallel paths. The first logic path is made of small devices and is configured to provide the logic function of the buffer/driver without the ability to drive large loads. Second and third logic paths have the logic function of the first logic path up to the last inverting stage. The last inverting stage in each path is a single device for driving the logic states of the buffer output. The second and third logic paths have power-gating that allows the input to the pull-up and pull-down devices to float removing gate-leakage voltage stress. When the second and third logic paths are power-gated, the first logic path provides a keeper function to hold the logic state of the buffer output. The buffer/driver may be an inverter, non-inverter, or provide a multiple input logic function.
摘要:
Virtual power-gated cells (VPC) are configured with control circuitry for buffering control signals and a power-gated block (PGB) comprising two or more NFETs for virtual ground rail nodes and PFETs for virtual positive rail nodes. Each VPC has a control voltage input, a control voltage output, a node coupled to a power supply voltage potential, and a virtual power-gated node that is coupled and decoupled from the power supply potential in response to logic states on the control input. The control signals are buffered by non-power-gated inverters before being applied to the input of a PGB. VPCs may propagate a control signal that is in phase with or inverted from a corresponding control signal at the control input. VPCs may be cascaded to create virtual power rails in chains and power grids. The control signals are latched at the cell boundaries or latched in response to a clock signal.
摘要:
A buffer/driver having large output devices for driving multiple loads is configured with three parallel paths. The first logic path is made of small devices and is configured to provide the logic function of the buffer without the ability to drive large loads. Second and third logic paths have the logic function of the first logic path up to the last inverting stage. The last inverting stage in each path is a single device for driving the logic states of the buffer output. The second and third logic paths have power-gating that allows the input to the pull-up and pull-down devices to float removing gate-leakage voltage stress. When the second and third logic paths are power-gated, the first logic path provides a keeper function to hold the logic state of the buffer output. The buffer may be an inverter, non-inverter, or provide a multiple input logic function.
摘要:
A wordline-to-bitline timing ring oscillator circuit for evaluating storage cell access time provides data on internal bitline access timing, and in particular the total wordline select-to-bitline read output timing. Columns of a storage array are connected in a ring, forming a ring oscillator. The bitline read circuit output of each column is connected to a wordline select input of a next column, with a net inversion around the ring, so that a ring oscillator is formed. The period of oscillation of the ring oscillator is determined by the total wordline select-to-bitline read circuit output timing for a first phase and the pre-charge interval time for the other phase, with the bitline read timing dominating. The circuit may be applied both to small-signal storage arrays, with the sense amplifier timing included within the ring oscillator period, or to large-signal storage arrays, with the read evaluate circuit timing included.
摘要:
Leakage current in logic circuitry is managed by coupling and decoupling the voltage potentials of the power supply from circuitry with large high leakage devices. Driver circuits comprise a low leakage logic path for holding logic states of the output. A high leakage logic path in parallel with the low leakage logic path is used to assert each logic state in the forward direction from input to output. The large output device in each high leakage path that enhances the current drive of a logic state on the output are leakage stress relieved by allowing their drive inputs to collapse after the output logic state has been asserted. The high leakage logic paths employ multiple stages with collapsing logic states that are generated in response to asserted logic states on the output and logic states of the low leakage logic path thus reducing the device sizes needed to control leakage.
摘要:
CMOS circuitry is partitioned into first and second logic circuit domains. The first logic circuit domain may be optionally a cuttable domains (C_Domains) where circuitry has power supply gating to reduce leakage power and non-cuttable domains (NC_Domains) where circuitry does not have power supply gating. Each output that couples signals from one logic circuit domain to another logic circuit is interfaced with a C_driver and a S_keeper which automatically assure that the output state is held when circuitry is power-gated put to reduce leakage power. The S_keeper and C_driver have low leakage circuits that maintain signal states and are not used for high speed operation.