An area effective forward/reverse body bias generator for within-die variability compensation

Abstract

To compensate the die-to-die and location correlated variation, we propose to split digital circuit to sub-mm-scale area controlling each area with an on-chip forward/reverse body bias generator (BBG). The proposed BBG is configured as a feedforward control system to achieve small area. The BBG is realized by combining a low output resistance DAC and a charge pump type level shifter. The BBG design is implemented with 1.2V thin gate oxide MOSFET in a 65nm CMOS technology. The simulation and measurement results show that the variation is compensated with an area overhead as small as 2%.