Completely digital on-chip circuit for local-random-variability measurement

A 45nm SOI completely digital on-chip circuit to measure local random variation of FET currents is presented. The design uses an array of independently selectable upper devices arranged in a stacked configuration with a single bottom device. Using a voltage-to-frequency converter and an on-chip counter, the circuit eliminates analog current measurements and enables rapid, all-digital measurement of single FET variability. ©2008 IEEE.