Nano-Quiescent Step-Down Converters from ST Save Energy and Space

STMicroelectronics’ ST1PS01 step-down converters are engineered for small size, low quiescent current, and high efficiency at all values of load current, to save energy and real-estate in keep-alive point-of-load supplies and IoT devices such as asset trackers, wearables, smart sensors, and smart meters.

Leveraging synchronous rectification, efficiency is 92% at 400mA full load and 95% when delivering just 1mA. Power-saving design features keep the quiescent current to a miserly 500nA and include a low-power voltage reference. There is also a pulse-frequency counter for controlling converter current at light load, with two high-speed comparators to help minimize output ripple.

Integrated feedback-loop compensation, soft-start circuitry, and power switches ensure a space-saving solution that requires just a few small-outline passives to complete the circuit. The typical inductor value is 2.2µH. In addition, output-voltage selection logic not only saves external voltage-setting components but also gives flexibility to configure modules digitally at manufacture or let the host system change the output voltage on the fly. Eight variants, each with four optional output-voltage settings, allow a choice of regulated outputs from 3.3V to 0.625V. All models feature a Power-good indicator (more info).