4A Monolithic synchronous step-down converter with high efficiency at light load

The ST1S50 device is a 500 kHz fixed frequency PWM synchronous step-down regulator. The ST1S50 operates from 4.0 V to 18 V input, while it regulates an output voltage as low as 0.8 V and up to 0.88 x VIN.

The ST1S50 device integrates a 95 mΩ high-side switch and a 69 mΩ synchronous rectifier allowing very high efficiency with very low output voltages.

The peak current mode control with a special PFM mode enables high efficiency at a light load.

The ST1S50 device is available in a VFDFPN10 3 x 3 x 1 mm - 10 leads package.

Key Features

  • 4 A output current
  • 4.0 V to 18 V input voltage
  • Output voltage adjustable from 0.8 V to 0.88 x VIN
  • 500 kHz switching frequency
  • High efficiency at light load
  • Programmable soft-start and enable
  • Integrated 95 mΩ and 69 mΩ power MOSFETs
  • All ceramic capacitor
  • Power Good
  • Cycle-by-cycle current limiting
  • Short-circuit protection
  • VFDFPN10 3 x 3 x 1 mm - 10 L


Technical Documentation

Product Specifications
Description Version Size
DS10105 DS10105: 4 A monolithic synchronous step-down switching converter with high efficiency at light load 4.0 702 KB

Publications and Collaterals

Description Version Size
Brochure Power management guide 09.2017 3 MB

Tools and Software

Evaluation Tools
Solution Evaluation Tools
eDesignSuite Support & Community

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
ST1S50PUR DFN10 3X3 Tape And Reel Active 0.788 1000 NEC EAR99 - 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**
ST1S50PUR ActiveDFN10 3X3 IndustrialEcopack2 0 0

(**) The Material Declaration forms available on st.com 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.