“…For ultra-low-power miniaturized systems, however, the area, power consumption and supply requirements make it difficult to employ a BGR as a voltage reference. A viable alternative featuring a low supply voltage, pW-level power consumption and small area is a subthreshold voltage reference [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. The two-transistor (2-T) reference in [ 4 ] achieves a fine LS of 0.044 %/V and a low TC of 54~176 ppm/°C, while consuming 5.5 pW and occupying a 1425 µm 2 area.…”