The CNNUC3: an analog I/O 64x64 CNN universal machine chip prototype with 7-bit analog accuracy

This paper describes a full-custom mixed-signal chip which embeds distributed optical signal acquisition, digitally-programmable analog parallel processing, and distributed image memory (cache) on a common silicon substrate. This chip, designed in a 0.5 μm CMOS standard technology contains around 1000000 transistors, 80% of which operate in analog mode. Chip functional features are in accordance to the CNN Universal Machine paradigm. The chip is capable to complete complex spatio-temporal image processing tasks within short computation time and using a low power budget. The internal circuitry of the chip has been designed to operate in robust manner with >7-bit equivalent accuracy in the internal analog operations, which has been confirmed by experimental measurements. Hence, to all practical purposes, processing tasks completed by the chip have the same accuracy than those completed by digital processors preceded by 7-bit digital-to-analog converters for image digitalization