This paper proposes a MOSFET-only, 20pA, 780ppm/oC current reference that consumes 23pW. The ultra-low power circuit exploits subthreshold-biased MOSFETs and a complementary-to-absolute temperature (CTAT) gate voltage to compensate for temperature dependency. The design shows low supply voltage sensitivity of 0.58%/V and a load sensitivity of 0.25%/V.
