ST1PS03 Datasheet 400 mA nano-quiescent synchronous step-down converter with digital voltage selection, Power Good and load switch Features 500 nA input quiescent current at V = 3.6 V (not switching) IN 92% typical efficiency at 10 mA load (V = 3.6 V, V = 2.5 V) IN OUT 100% duty cycle 1.8 V to 5.5 V input operating range Undervoltage lockout: 1.57 V (V falling, typ.) IN Up to 400 mA output current capability Low power control operation for the best efficiency Embedded soft-start circuit Tiny external components: L = 2.2 H typ. Selectable output voltages: 1.6 V to 3.3 V Output voltage Power Good 1.5% output voltage accuracy (V , T = 25 C) OUT A Dynamic output voltage selection (D0, D1 and D2) Load switch controlled by AUX input Available in TQFN12 package Applications Wearable applications Personal tracking monitors Product status link Smart watches, sport bands Energy harvesting, wireless sensors ST1PS03 Wearable and fitness accessories Industrial sensors, portable low power devices Single cell Li-Ion battery applications Bluetooth Low Energy Zigbee Description The ST1PS03 is a nano-quiescent miniaturized synchronous step-down converter, which is able to provide up to 400 mA output current with an input voltage ranging from 1.8 V to 5.5 V. This converter is specifically designed for applications where high efficiency, PCB size and thickness are the key factors. The output voltage can be set using three digital control inputs, a V from 1.6 V OUT to 3.3 V can be dynamically selected. Thanks to the enhanced PCC (peak current control) the ST1PS03 reaches very high efficiency conversion using just a 2.2 H inductor and two small capacitors. An advanced design circuitry is developed to minimize the quiescent current. The device embeds a controlled switch accessible from VIN AUX, to supply a subsystem. Finally, it is available in thin plastic package. DS13801 - Rev 1 - September 2021 www.st.com For further information contact your local STMicroelectronics sales office.ST1PS03 Application schematic 1 Application schematic Figure 1. ST1PS03 application schematic Logic input PGOOD EN L1 R1 Vout Vin VIN SW S T 1 P S 0 3 C1 VOUT Vcc GPIO C3 Vin AUX VIN AUX GND C2 Low voltage D0 C4 Vout AUX system VOUT AUX Logic D1 inputs Logic input AUX D2 Table 1. Typical external components Component Description Value Size - imperial (metric) C , C Ceramic capacitor with low ESR values 1 3 10 F 0603 (1608) C , C Ceramic capacitor with low ESR values 2 4 L1 Inductor 2.2 H 0806 (2016) R Pull-up resistor 1 M 0402 (1005) 1 DS13801 - Rev 1 page 2/25