A 5.5 ppm/℃, 4.5-nW Wide Temperature Range Sub-threshold CMOS Voltage Reference

A novel complementary-to-absolute-temperature (CTAT) generator-based voltage reference circuit is proposed. The design features a resistor-less, ultra-low-power, sub-1 V MOSFET-only sub-threshold voltage reference compatible with digital CMOS processes, making it suitable for low-power and compact applications. The proposed circuit achieves a reference voltage of 0.581 V and utilizes highly linear proportional-to-absolute-temperature (PTAT) and CTAT generators to ensure a low temperature coefficient of 5.5 ppm/℃ across a wide temperature range from −50℃ to 150℃. The circuit’s analytical behavior is modeled, and extensive post-layout analog simulations in a 0.18-μm CMOS process validate the design performance. It demonstrates excellent line sensitivity of 0.1%/V across a supply voltage range of 0.8 to 3 V and achieves a power supply ripple rejection (PSRR) of −53 dB at 100 Hz. The circuit occupies an area of only 0.005315 mm2 and consumes 4.5 nW at 27℃. The compact and efficient design addresses the challenges of achieving stability, scalability, and low power in modern CMOS-based systems.