Monolithic synchronous step-down regulator

The ST1S10 is a high efficiency step-down PWM current mode switching regulator capable of providing up to 3 A of output current. The device operates with an input supply range from 2.5 V to 18 V and provides an adjustable output voltage from 0.8 V (VFB) to 0.85 * VIN_SW[VOUT= VFB * (1 + R1/R2)]. It operates either at a 900 kHz fixed frequency or can be synchronized to an external clock (from 400 kHz to 1.2 MHz). The high switching frequency allows the use of tiny SMD external components, while the integrated synchronous rectifier eliminates the need for a Schottky diode. The ST1S10 provides excellent transient response, and is fully protected against thermal overheating, switching overcurrent and output short-circuit.

The ST1S10 is the ideal choice for point of load regulators or LDO pre-regulation.

Key Features

  • Step-down current mode PWM regulator
  • Output voltage adjustable from 0.8 V
  • Input voltage from 2.5 V up to 18 V
  • 2% DC output voltage tolerance
  • Synchronous rectification
  • Inhibit function
  • Synchronizable switching frequency from 400 kHz up to 1.2 MHz
  • Internal soft start
  • Dynamic short-circuit protection
  • Typical efficiency: 90%
  • 3 A output current capability
  • Standby supply current: max. 6 μA over temperature range
  • Operative junction temp.: from -40 °C to 125 °C

Circuit Diagram

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Technical Documentation

Product Specifications
Description Version Size
DS5438 DS5438: 3 A, 900 kHz, monolithic synchronous step-down regulator IC 6.0 768 KB
Application Notes
Description Version Size
AN2620 AN2620: 3 A high-frequency synchronous 900 kHz step-down converter based on the ST1S10 3.1 1 MB
AN2754 AN2754: Buck high-brightness LED driver based on the ST1S10 step-down DC-DC converter voltage regulator 1.0 302 KB

Publications and Collaterals

Description Version Size
Brochure Power management guide 09.2017 3 MB

Tools and Software

Evaluation Tools
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Sample & Buy

Part Number Package Packing Type Marketing Status Unit Price (US$) * Quantity ECCN (EU) ECCN (US) Country of Origin More info Order from ST Order from Distributors
ST1S10PHR PowerSO-8 Tape And Reel Active 0.693 1000 NEC EAR99 CHINA MORE INFO Get Sample Add to cart DISTRIBUTOR AVAILABILITY
ST1S10PUR DFN8 4x4 Tape And Reel Active 0.693 1000 NEC EAR99 MALAYSIA MORE INFO Get Sample Add to cart DISTRIBUTOR AVAILABILITY

(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office  or our Distributors

Quality & Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
ST1S10PHR ActivePowerSO-8IndustrialEcopack2 0 0
ST1S10PUR ActiveDFN8 4x4IndustrialEcopack2 0 0

(**) The Material Declaration forms available on may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.