Product overview
Description
The ST1S03 is a step-down DC-DC converter optimized for powering a low voltage digital core in HDD applications and, generally, to replace the high current linear solution when the power dissipation may cause a high heating of the application environment. It provides up to 1.5 A over an input voltage range of 3 V to 16 V. A high switching frequency (1.5 MHz) allows the use of tiny surface-mount components: as well as the resistor divider to set the output voltage value, only an inductor, a Schottky diode and two capacitors are required. Besides, a low output ripple is guaranteed by the current mode PWM topology and by the use of low ESR SMD ceramic capacitors. The device is thermal protected and current limited to prevent damages due to an accidental short-circuit. The ST1S03 device is available in a DFN6D package.
-
All features
- Step-down current mode PWM (1.5 MHz) DC-DC converter
- 2% DC output voltage tolerance
- Internal soft-start for STARTUP current limitation and power on delay of 50 - 100 μs
- Typical efficiency: > 70% over all operating conditions
- 1.5 A output current capability
- Not switching quiescent current: max 2.5 mA over temperature range
- Switch VDS: max. 350 mV at ISW= 750 mA
- Uses tiny capacitors and inductors
- Available in DFN6D 3 x 3 mm package with exposed pad
Circuit Diagram
eDesignSuite
eDesignSuite is a comprehensive set of easy-to-use design-aid utilities ready to help you streamline the system development process with a wide range of ST products.
Power Management Design Center
Thermal-electrical Simulators for Components
Signal Conditioning Design Tool
NFC/RFID Calculators
Choose design tool: 
Power Management Design Center
Power Supply Design Tool
• SMPS design, by topology, by type and by product
• PFC design with analog and digitial control
• Supports various PCB configurations
Choose type: DC/DC AC/DC Solar Battery Charger
Power Management Design Center
LED Lighting Design Tool
• Handles AC-DC and DC-DC design in common topologies
• Displays interactive and annotated schematic
• Provides current/voltage graphs, Bode plots, efficiency curves and power-loss data
Choose type: DC/DC AC/DC
Power Management Design Center
Digital Power Workbench
• Provides a step-by-step optimized design of power section and control loop
• Generates the STM32Cube embedded software package for custom applications and allows firmware project generation, compatible with multiple STM32 IDEs
Power Management Design Center
Power Tree Designer
• Specify input/output power for each node in the tree
• Check for consistency
• Design each individual node
Choose design tool: 
Thermal-electrical Simulators for Components
AC Switches Simulator
• Select ratings and application waveforms
• Get junction temperature and blocking voltage graphs
• Search and sort suitable devices
Thermal-electrical Simulators for Components
Rectifier Diodes Simulator
• Select ratings and application waveforms
• Estimate power losses
• Search and sort suitable devices
Thermal-electrical Simulators for Components
STPOWER Studio
• Supports long mission profiles
• Provides power loss and temperature graphs
• Helps define heatsink thermal properties
Thermal-electrical Simulators for Components
Twister Sim
• Help select the right ViPOWER Automotive power device
• Supports load-compatibility, wiring harness optimization, fault condition impact and diagnostic analysis
• Supports various PCB configurations
Thermal-electrical Simulators for Components
TVS Simulator
• Specify system ratings and surge waveform
• Search and sort suitable devices
Thermal-electrical Simulators for Components
Estimate
• Build simple schematics and firmware inputs in minutes
• Quickly generate reliable estimates of battery life, system power consumption and bill of materials costs
Thermal-electrical Simulators for Components
PCB Thermal Simulator
• Thermal analysis of a PCB from Gerber files.
• Possibility to add heat sources, heat sinks, copper areas and thermal paths.
• Powerful server-side engine for rendering and simulation.
• Thermal results shown graphically via 2D table.
Choose design tool: 
Signal Conditioning Design Tool
Active Filters
• Handles multi-stage-designs and common topologies
• Returns circuit component values
• Provides gain, phase and group delay graphs
• Low Pass, High Pass and Band Pass
Signal Conditioning Design Tool
Comparators
• Handles most common configurations
• Returns circuit components values
• Provides I/O signal waveforms
• Inverting, Non Inverting, Window
Signal Conditioning Design Tool
Low side Current Sensing
• Returns circuit component values
• Provides current error graphs
Signal Conditioning Design Tool
High side Current Sensing
• Provides current error graphs.
• Help to select the right High side current sensing and shunt devices.
Choose design tool: 
NFC/RFID Calculators
NFC Inductance
• Input geometry and substrate properties
• Get antenna impedance
NFC/RFID Calculators
UHF Link Budget
• Enter forward and reverse link characteristics
• The tool returns link budget estimate
NFC/RFID Calculators
NFC Tuning Circuit
• Enter antenna parameter and matching target
• Select the topology of the matching network
• The tool returns component values for the desired design targets
