J. Tschanz

Dynamic-sleep transistor and body bias for active leakage power control of microprocessors

Sleep transistors and body bias are used to control active leakage for a 32b integer execution core implemented in a 100nm dual V, CMOS technology. A PMOS sleep transistor degrades performance by 4% but offers 20/spl times/ leakage reduction which is further improved with body bias. Time constants for leakage convergence range from 30ns to 300ns allowing 9-44% power savings for idle periods greater than 100 clock cycles.

Adaptive Frequency and Biasing Techniques for Tolerance to Dynamic Temperature-Voltage Variations and Aging

Temperature, voltage, and current sensors monitor the operation of a TCP/IP offload accelerator engine fabricated in 90nm CMOS, and a control unit dynamically changes frequency, voltage, and body bias for optimum performance and energy efficiency. Fast response to droops and temperature changes is enabled by a multi-PLL clocking unit and on-chip body bias. Adaptive techniques are also used to compensate performance degradation due to device aging, reducing the aging guardband.

Measurements and analysis of SER-tolerant latch in a 90-nm dual-V/sub T/ CMOS process

We designed a soft error rate (SER) tolerant latch utilizing local redundancy. We implemented a test chip containing both the standard and SER-tolerant latches in a 90-nm dual-V/sub T/ CMOS process. Accelerated measurements with a neutron beam at Los Alamos National Laboratory demonstrated 10/spl times/ better reliability of the SER-tolerant latch over the standard latch at no speed degradation. The worst case energy and area penalties were 39% and 44%, respectively. Both the energy and area penalties are negligible for standard-latch transistor sizes at least double the minimum width. We analyzed the effects of the recovery time, threshold voltage assignment, and leakage on the SER robustness. The proposed latch can improve reliability of critical sequential logic elements in microprocessors and other circuits.

Neutron soft error rate measurements in a 90-nm CMOS process and scaling trends in SRAM from 0.25-/spl mu/m to 90-nm generation

The neutron soft error rate (SER) dependency on voltage and area was measured for a state-of-the-art 90-nm CMOS technology. The SER increased by 18% for a 10% reduction in voltage, and scaled linearly with diode area. The measured SER per bit of SRAMs in 0.25 /spl mu/m, 0.18 /spl mu/m, 0.13 /spl mu/m, and 90 nm showed an increase of 8% per generation.

Effectiveness of adaptive supply voltage and body bias for reducing impact of parameter variations in low power and high performance microprocessors

Test chip measurements show that adaptive V/sub CC/ is useful for reducing impacts of parameter variations on frequency, active power and leakage power of microprocessors. Using adaptive V/sub CC/ together with adaptive V/sub BS/ or WID-V/sub BS/ is much more effective than using any of them individually.

A TCP offload accelerator for 10 Gb/s Ethernet in 90-nm CMOS

This programmable engine is designed to offload TCP inbound processing at wire speed for 10-Gb/s Ethernet, supporting 64-byte minimum packet size. This prototype chip employs a high-speed core and a specialized instruction set. It includes hardware support for dynamically reordering out-of-order packets. In a 90-nm CMOS process, the 8-mm/sup 2/ experimental chip has 460 K transistors. First silicon has been validated to be fully functional and achieves 9.64-Gb/s packet processing performance at 1.72 V and consumes 6.39 W.

Design optimizations of a high performance microprocessor using combinations of dual-V/sub T/ allocation and transistor sizing

Joint optimizations of dual-V/sub T/ allocation and transistor sizing reduce low-V/sub T/ usage by 36%-45% and leakage power by 20% in a high performance microprocessor, with minimal impact on total active power and die area. An enhancement of the optimum design allows processor frequency to be increased efficiently during manufacturing.

Numerical analysis of domain wall propagation for dense memory arrays

This paper presents numerical analysis of domain wall propagation for dense embedded memory applications. Self-consistent simulation framework based on Four Component Spin Transport Model and Landau-Lifshitz-Gilbert equation is able to capture domain wall motion in terms of critical current density requirement, domain wall velocity, and power dissipation. Effect of patterned notches on memory stability, domain wall velocity and nanostrip resistance are also presented. Finally, the proposed simulation framework is used to investigate performance, scalability and organization of the domain wall motion based memory structure.

A 25 GHz 32 b integer-execution core in 130 nm dual-V/sub T/ CMOS

A 32 b integer execution core implements 12 instructions. Circuit and body bias techniques together increase the core clock frequency to 5 GHz. In a 130 nm six-metal dual-V/sub T/ CMOS process, the 2.3 mm/sup 2/ prototype contains 160 k transistors, with RF-ALU units dissipating 515 mW at 1.6 V.

Leakage and process variation effects in current testing on future CMOS circuits

Barriers to technology scaling, such as leakage and parameter variations, challenge the effectiveness of current-based test techniques. This correlative multiparameter test approach improves current testing sensitivity, exploiting dependencies of transistor and circuit leakage on operating frequency, temperature, and body bias to discriminate fast but intrinsically leaky ICs from defective ones.