A Picowatt CMOS Voltage Reference Operating at 0.5-V Power Supply With Process and Temperature Compensation for Low-Power IoT Systems

This brief presents a picowatt PVT-insensitive CMOS voltage reference with ultra-low supply voltage. The core circuit of the proposed reference consists of three subthreshold-biased PMOS transistors, and process and temperature compensation are achieved by employing the width-induced
$V_{\mathrm{ th}}$
modulation and self-body-biasing techniques. The reference was implemented in a standard 180-nm CMOS process. With a power supply of 0.5 V at 25 °C, the measurement results of 16 chips show a mean reference voltage of 288 mV with a standard deviation of 1.65 mV
$(\sigma /\mu \,\,=$
0.57%). The line sensitivity is 0.23%/V with a minimum supply voltage of 0.5 V. The average temperature coefficient is 90 ppm/°C after batch trimming over a temperature range of −10°C to 100°C. The power consumption at room temperature is 500 pW, and the active area is 0.0029 mm2.