A Spur-free, 150-mA Buck Regulator with 96.3% Peak-Efficiency and 77.2% Minimum Efficiency at 10-μA Load for Microcontrollers with Noise-Sensitive ADCs

A buck regulator with hybrid adaptive-on- time/hysteretic control and universal spur-free switching for Microcontroller Units (MCUs) is proposed. The controller enables achieving high efficiency across a wide load range (10μA-150mA) and eliminates all spurious noise within the regulator. Therefore, it offers a single powering solution for MCUs that require both low-noise operation and high efficiency. The regulator is designed in 65nm CMOS, and occupies an active area of 0.18mm
²
. It operates from 2.7-4.2V input and produces a 1.2-3.3V output. The regulator’s peak efficiency is 96.3%, while its minimum efficiency at 10-μA load is 77.2%. Due to its spur- free operation, the regulator is used to directly power a high- performance 14-bit ADC without any degradation in the ADC’s dynamic range or effective number of bits and without using any post filtering or post regulation.