SOTB technology, which enables perpetually reliable CPU for IoT applications

Sensors and wearable systems are expanding to make the IoT era. Requirements of the devices to realize the expansion of the systems are low-power LSIs which can operate eternally with energy harvesting power sources. The LSI should operate fast enough to deal with the data, followed by sleep mode to save the energy. The data during sleep mode should be reliably stored for the next intermittent operation. This paper introduces and describes 65nm SOTB (Silicon on Thin Buried oxide) technology and characteristics of CPU which was designed and fabricated using the 65nm SOTB technology. A 32 bit CPU achieves 28 MHz operation at low power consumption of 14.3uW/MHz at 0.75V. Sleep current is reduced to 108nA with negative body bias of -1.06V applied by on chip 15nA body bias generator. SER of FFs using the SOTB becomes 1/200 of Bulk in sleep mode, which makes sure the reliable data store at sleep mode.

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