Abstract: A multi-threshold integrated circuit (IC) with reduced subthreshold leakage and method of reducing leakage. Selectable supply switching devices (NFETs and/or PFETs) between a logic circuit and supply connections (Vdd and Ground) for the circuit have higher thresholds than normal circuit devices. Some devices may have thresholds lowered when the supply switching devices are on. Header/footer devices with further higher threshold voltages and widths may be used to further increase off resistance and maintain/reduce on resistance. Alternatively, high threshold devices may be stacked to further reduce leakage to a point achieved for an even higher threshold. Intermediate supply connects at the devices may have decoupling capacitance and devices may be tapered for optimum stack height and an optimum taper ratio to minimize circuit leakage and circuit delay.

Abstract: Low-conductance and high-conductance IV characteristics (models) are created using the low and high end of their body voltage ranges, respectively. The body voltage of the device (FET) is initialized to the low end of range at time zero, and then a transient, two dimensional sweep of gate and drain voltages is performed. Drain currents are measured in this two dimensional region and are used to create a piecewise, linear IV model of device. The process is repeated for the highest body voltage. This process differs significantly from prior art bulk device characterization techniques, which did not have to initialize body voltage or perform a transient analysis. The body voltage is modulating during the switching event due to the gate-to-body and diffusion-to-body coupling; and thus only a transient analysis can properly model these coupling effects.

Abstract: An integrated circuit that may include an array such as a static random access memory (SRAM) with high threshold device array devices and in selected other devices to reduce leakage. Devices with high threshold have a thicker gate oxide or a high k dielectric gate oxide that is selected based on threshold voltage (VT) variations with gate oxide dielectric type or gate oxide thickness for the particular technology, e.g., PD SOI CMOS. High threshold devices may be used in non-core circuits, e.g., test circuits. Also, non-critical paths may be identified and a non-critical path margin identified. A thicker device threshold is selected for non-critcal path FETs based on the non-critical path margin. Non-critical path delays are re-checked. FETs are formed with the selected thicker gate oxide for any non-critical paths passing the re-check and in array FETs with non-selected FETs being formed with normal gate oxide thickness.

Abstract: A 64-bit adder implemented in partially depleted silicon on insulator technology and having two levels of lookahead uses a dynamic eight-bit carry module containing a cascode evaluation tree employing a chain of source followers that feeds a sense amplifier, thereby obtaining benefits from high initial drive, low variation in body voltage, resulting in low variation in history-dependent delay, reduced noise sensitivity and noise-based delay.

Abstract: An integrated circuit that may include an array such as a static random access memory (SRAM) with high threshold device array devices and in selected other devices to reduce leakage. Devices with high threshold have a thicker gate oxide or a high k dielectric gate oxide that is selected based on threshold voltage (VT) variations with gate oxide dielectric type or gate oxide thickness for the particular technology, e.g., PD SOI CMOS. High threshold devices may be used in non-core circuits, e.g., test circuits. Also, non-critical paths may be identified and a non-critical path margin identified. A thicker device threshold is selected for non-critcal path FETs based on the non-critical path margin. Non-critical path delays are re-checked. FETs are formed with the selected thicker gate oxide for any non-critical paths passing the re-check and in array FETs with non-selected FETs being formed with normal gate oxide thickness.

Abstract: A 64-bit adder implemented in partially depleted silicon on insulator technology and having two levels of lookahead uses a dynamic eight-bit carry module containing a cascode evaluation tree employing a chain of source followers that feeds a sense amplifier, thereby obtaining benefits from high initial drive, low variation in body voltage, resulting in low variation in history-dependent delay, reduced noise sensitivity and noise-based delay.

Abstract: A 64-bit adder implemented in partially depleted silicon on insulator technology and having two levels of lookahead uses a dynamic eight-bit carry module containing a differential pass-gate evaluation tree employing a chain of source followers that feeds a sense amplifier, thereby obtaining benefits from high initial drive, low variation in body voltage, resulting in low variation in history-dependent delay, reduced noise sensitivity and noise-based delay.

Abstract: Low-conductance and high-conductance IV characteristics (models) are created using the low and high end of their body voltage ranges, respectively. The body voltage of the device (FET) is initialized to the low end of range at time zero, and then a transient, two dimensional sweep of gate and drain voltages is performed. Drain currents are measured in this two dimensional region and are used to create a piecewise, linear IV model of device. The process is repeated for the highest body voltage. This process differs significantly from prior art bulk device characterization techniques, which did not have to initialize body voltage or perform a transient analysis. The body voltage is modulating during the switching event due to the gate-to-body and diffusion-to-body coupling; and thus only a transient analysis can properly model these coupling effects.

Abstract: A method for reducing a hysteresis effect in silicon-on-insulator CMOS circuits includes the steps of providing a circuit having CMOS objects, defining a beta ratio; resizing the CMOS objects based on the beta ratio, determining if the objects are a minimum size based on predetermined size criteria, if the objects are larger than the minimum size, defining a scaling factor based on a performance level of the object and resizing the object based on the scaling factor such that delay variations of the resized circuit are substantially constant. Also, a computer program product is provided for reducing the hysteresis effect.

Abstract: An emitter coupled logic circuit includes a series connected PNP transistor and diode to improve the pull-up delay and power consumption. The biasing of the PNP transistor is established by utilizing existing voltage levels in the emitter coupled logic circuit with no extra biasing circuit and power. Complementary push-pull emitter coupled logic circuit configurations with no power wasted in the biasing of the push-and-pull transistors can be derived based on this PNP pull-up scheme and NPN active-pull-down scheme.

Abstract: High-speed low-power emitter coupled logic (ECL) and non-threshold logic (NTL) circuits are disclosed wherein an ac-coupled complementary push-pull output stage is utilized. The circuits utilize two capacitors to couple an ac-pulse derived from a replica of an input signal to the bases of the complementary PNP-NPN push-pull transistors to provide a large transient current, thus realizing high-speed operation with very low dc power dissipation. The coupling scheme allows a very low switch current to be used for the logic (current switch) stage to maintain the proper logic levels while avoiding the impact on the switching speed by the large pull-up resistors of the logic stage.

Abstract: A high speed multiplexer circuit is described which includes a plurality of input bipolar transistors and a reference bipolar transistor. The input and reference transistors have their emitters commonly coupled to an emitter current supply and their collectors coupled to a collector supply. The collector of the reference transistor is coupled to the collector supply through an impedance. A reference potential is connected to the base of the reference bipolar transistor and biases it for conduction. An input signal to be multiplexed is connected to the base of each of the input bipolar transistors and a diode circuit is coupled between the base of each of the input bipolar transistors and a switch input. A switch input, in a first state, causes the diode circuit to conduct and clamp the base of an input transistor, to prevent it from responding to a signal input.

Abstract: An ECL circuit having an output circuit with improved pull-down characteristics. An active pull-down circuit is provided by a p-channel JFET which includes a back gate connection or a merged p-channel JFET/NPN device. The gate and/or back gate are switched, providing a lowering of the device impedance during switching of the device from pull-up to pull-down operation, resulting in an improved pull-down speed.

Abstract: This invention relates generally to Static Random Access Memory (SRAM) cells and more particularly, relates to a SRAM cell wherein soft-error due to .alpha.-particle radiation is reduced by permitting the potential at the common-emitter node of the cross-coupled transistors of the memory cell to swing freely. Still more particularly, it relates to a SRAM cell wherein the common-emitter node of the cell is decoupled from a heavily capacitively loaded word line with its common constant current source by means of a constant current source or current mirror disposed in each cell between the common-emitter node and the word line.