A Time-Slicing Ring Oscillator for Capturing Time-Dependent Delay Degradation and Power Supply Voltage Fluctuation

Takumi UEZONO  Kazuya MASU  Takashi SATO  

IEICE TRANSACTIONS on Electronics   Vol.E93-C    No.3    pp.324-331
Publication Date: 2010/03/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E93.C.324
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Circuits and Design Techniques for Advanced Large Scale Integration)
voltage measurement,  spatial voltage drop fluctuation,  process variation,  power/signal integrity,  

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A time-slicing ring oscillator (TSRO) which captures time-dependent delay degradation due to periodic transient voltage drop on a power supply network is proposed. An impact of the supply voltage fluctuations, including voltage drop and overshoot, on logic circuit delay is evaluated as a change of oscillation frequency. The TSRO is designed using standard logic cells so that it can be placed almost anywhere in a digital circuit wherein supply voltage fluctuation is concerned. We also propose a new procedure for reconstructing supply voltage waveform. The procedure enables us to accurately monitor time-dependent, effective supply voltages. The -1 dB bandwidth of the TSRO is simulated to be 15.7 GHz, and measured time resolution is 131 ps. Measurement results of a test chip using 90-nm standard CMOS process successfully proved the feasibility of both delay degradation and effective supply voltage fluctuation measurements. Measurement of spatial voltage drop fluctuation is achieved.