An energy-efficient threshold voltage extractor with the burst-mode operation and extended long-term variations using FVF

M. B. Ghaznavi-Ghoushchi | A.R.Kariman | A.R.Shamshiri

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URL :   http://research.shahed.ac.ir/WSR/WebPages/Report/PaperView.aspx?PaperID=158829
Date :  2020/10/01
Publish in :    Microelectronics Journal

Link :  https://doi.org/10.1016/j.mejo.2020.104862
Keywords :CMOS, Threshold voltage, Vth extractor, Circuit failure, Aging, Ultra-low energy, Circuit reliability,

Abstract :

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There are various circuits for extracting threshold voltage (V_th) of CMOS transistors. In this work, we have introduced an energy-efficient threshold voltage extractor with high precision and extended long-term variations. Considering fabrication prohibits, a switched capacitor (SC) has been used instead of a high resistive poly resistor. In order to reduce the power consumption of the V_th extractor, the circuit operates in the burst-mode (energy-efficient). Also, to reduce the glitches in the structure of the SC, a 3rd-order low-pass filter and a replica branch are used. Furthermore, the flipped voltage follower (FVF) structure extends threshold voltage variations over time to measure V_th aging via reasonable resolution data converters. The circuit has been evaluated using 65nm standard CMOS model. The range of V_th variations over 180 months is between 239.4mV and 278.9mV, which is equivalent to a 16.5 change. The power consumption of the entire circuit is less than 11nW. This circuit is a good candidate to function as a benchmark for the efficiency of high-reliability circuits and aging sensors.