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The design, analysis, and implementation of an accurate delay circuit used to synthesize critical paths in a microprocessor system are presented. The delay circuit includes a novel 64-step programmable calibration delay line that is highly uniform across a wide range of supply voltages and a reconfigurable delay path with tunable delay sensitivity to voltage variations. The calibration delay line generates delay step in picosecond range, which is less than 1% of the clock cycle time for the microprocessor. The reconfigurable path is capable of increasing voltage sensitivity of the delay circuit by 40% and emulating the steeper frequency versus voltage slope of the microprocessor in low-voltage domain. The proposed circuit is implemented inside the critical path monitor block placed on a test microprocessor core fabricated using 22-nm silicon-on-insulator CMOS process. Measurement results from nine test cores show that the circuit tracks microprocessor timing margin change with an error less than 1.3% of the core operating frequency over a wide supply voltage range. [ABSTRACT FROM PUBLISHER]

Transistor mismatch data and analysis from poly/SiON and high-k/metal-gate (HKMG) bulk CMOS technologies are presented. It is found that the traditional mismatch figure of merit from the Pelgrom plot (AVT) continuously scales down as technology advances. Furthermore, the AVT values for both nFET and pFET in the HKMG technology are significantly reduced from poly/SiON technologies. By normalizing the mismatch data against electrical oxide thickness (TINV), threshold voltage (VTH), and effective work function, a direct comparison of the mismatch data from various technologies is made. The differences in nFET and pFET mismatch behaviors in both poly/SiON and HKMG technologies are discussed in detail. Correlation between transistor VTH mismatch and flicker noise variation is observed in both poly/SiON and HKMG technologies. Finally, it is quantitatively demonstrated that effective work function variation does not generate significant VTH variability in the present HKMG technology. [ABSTRACT FROM AUTHOR]