A CMOS switched-capacitor fractional bandgap reference

An architecture for generating a voltage reference at a fraction of the silicon bandgap is proposed. It uses a two-phase switched-capacitor network to add multiples and fractions of V
_BE
and ΔV
_BE
to achieve a near zero temperature coefficient without the use of resistors or op-amps. The 0.0055mm
²
circuit, implemented entirely on-chip in 65nm CMOS, produces a voltage of 423mV, has a measured σ of 2.2%, and consumes 138nA while operating at a supply as low as 750mV at -35°C.