1-V 4.91-nW wide-temperature-range subthreshold bandgap reference with substrate bias technique

Biasing MOSFET in subthreshold region is an approach to reduce power of sub-bandgap references (Sub-BGRs) at low supply. However, conventional subthreshold Sub-BGRs cannot operate in low temperature because proportional-to-absolute-temperature (PTAT) voltage’s temperature characteristics changes. In this work, substrate bias technique is introduced to keep PTAT voltage available in much wider temperature range. In the standard 180 nm CMOS, the proposed 4.91 nW Sub-BGR exhibits a minimum temperature coefficient (TC) of 85 ppm/°C from -55 to 125 °C.