We present a design and characterization method for a scalable ultra-wide voltage range (UWVR) SRAM bitcell array, targeting a minimum voltage prediction, high yield and Si-CAD correlation within 5%. The experimental validation is first performed in bulk CMOS 65nm, then confirmed in 28nm FDSOI. Over 10x energy gain is achieved from 1.2V down to 0.35V range while measuring high speed at nominal voltage.