We present a supply supervisory circuit that makes use of an adaptively biased current comparator achieving fast response time (1.8 μ s) while consuming very low quiescent current (Iq). A Burst mode charge-pump is used to ensure monitoring down to 0.75V. This is the lowest reported common monitoring and operating supply for supervisory circuits. Fabricated in 130nm CMOS, this work achieves an Iq(nA) x Delay (μ s) FoM of 29, a 70x improvement over state-of-the-art supply supervisory circuits. © 2021 IEEE.