1.2-V Supply, 100-nW, 1.09-V Bandgap and 0.7-V Supply, 52.5-nW, 0.55-V Subbandgap Reference Circuits for Nanowatt CMOS LSIs

This paper presents bandgap reference (BGR) and sub-BGR circuits for nanowatt LSIs. The circuits consist of a nano-ampere current reference circuit, a bipolar transistor, and proportional-to-absolute-temperature (PTAT) voltage generators. The proposed circuits avoid the use of resistors and contain only MOSFETs and one bipolar transistor. Because the sub-BGR circuit divides the output voltage of the bipolar transistor without resistors, it can operate at a sub-1-V supply. The experimental results obtained in the 0.18-μm CMOS process demonstrated that the BGR circuit could generate a reference voltage of 1.09 V and the sub-BGR circuit could generate one of 0.548 V. The power dissipations of the BGR and sub-BGR circuits corresponded to 100 and 52.5 nW.