A 36 nW trimless voltage reference with low sensitivity to PVT variations

In this paper a trimless ultra-low-power voltage reference with low sensitivity to process, voltage and temperature (PVT) is presented. The design uses a cascaded proportional to absolute temperature (PTAT) voltage generator to produce a voltage independent of process and line variations. The voltage is compensated in temperature by using a temperature-dependent current-load that changes the bias point of the voltage generator. The voltage reference is simulated over PVT in a 28 nm FD-SOI process and a mean value of 386 mV with absolute accuracy of
$\pm 3.8\%$
is found. Spread across process corners is 4.7%
$(3\sigma/\mu)$
. Power consumption is 36 nW at 25°C and 0.8 V. Line sensitivity is better than 0.14 %/V and the worst temperature coefficient (T.C.) from 0°C to 60°C is 91.8 ppm/°C.