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 400 mA full load and 95% when delivering just 1 mA. Power-saving design features keep the quiescent current to a miserly 500 nA 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.
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| ST1PS01 application schematic. |
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 2.2 µH. 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 3.3 V to 0.625 V. All models feature a Power-good indicator.
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| Efficiency vs load, VOUT= 3.3 V. |
A wide input-voltage range, from 1.8 V to 5.5 V, further enhances flexibility for designers by allowing various battery chemistries or configurations as simple as a single lithium cell and extending runtime as the battery discharges. ST1PS01 regulators are also ideal for devices powered from energy-harvesting systems and feature a low noise-architecture that allows use in noise-sensitive applications.
An evaluation board, STEVAL-1PS01EJR, helps developers quickly understand how to take advantage of the ST1PS01’s high energy efficiency and feature integration.
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| Evaluation board based on the ST1PS01EJR 400 mA nano-quiescent synchronous step-down converter. |
ST1PS01 regulators are now in full production, packaged as 400 µm-pitch flip-chip devices measuring just 1.11 mm × 1.41 mm, and priced from $0.686 for orders of 1000 pieces.
