A 100-nW sensitive differential drive CMOS RF-DC converter implemented in a 0.18 μm technology is developed. The circuit is meant to be used as a bootstrap or start-up circuit in an energy harvesting application. The 66-stage rectifier is tapered for optimal performance. Driving a 10 MO load, the circuit has a measured output greater than 100 mV, for an input power of 100 nW at 350 MHz. For an input power of 100 μW at 350 MHz, the circuit is measured to have an output of 1.25 V, for an output load of 10 MO. Measurement results include balun and matching network losses. For infinite output resistive loads, the circuit is simulated to have an output greater than 1 V, for input powers larger than-30 dBm. © 2016 IEEE.