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  • The ST1S31 device is an internally compensated 1.5 MHz fixed-frequency PWM synchronous step-down regulator. The ST1S31 operates from 2.8 V to 5.5 V input, while it regulates an output voltage as low as 0.8 V and up to VIN.

    The ST1S31 integrates a 60 mΩ high-side switch and a 45 mΩ synchronous rectifier allowing very high efficiency with very low output voltages.
    The peak current mode control with internal compensation delivers a very compact solution with a minimum component count.
    The ST1S31 device is available in 3 mm x 3 mm, 8 lead VFDFPN and SO8 packages.

    Key Features

    • 3 A DC output current
    • 2.8 V to 5.5 V input voltage
    • Output voltage adjustable from 0.8 V
    • 1.5 MHz switching frequency
    • Internal soft-start and enable
    • Integrated 60 mΩ and 45 mΩ power MOSFETs
    • All ceramic capacitor
    • Power Good (POR)
    • Cycle-by-cycle current limiting
    • Current foldback short-circuit protection
    • VFDFPN 3 x 3 - 8L, SO8 packages

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Evaluation Tools

    • Part Number

      3 A / 1.5 MHz step-down synchronous switching regulator based on the ST1S31 in DFN 3x3 package

      3 A / 1.5 MHz step-down synchronous switching regulator based on the ST1S31 in SO-8 package

00 Files selected for download

Technical Documentation

    • Description Version Size Action
      DS8977
      3 A DC step-down switching regulator
      5.0
      1.5 MB
      PDF
      DS8977

      3 A DC step-down switching regulator

    • Description Version Size Action
      TN1224
      Mounting instructions for SMD (surface mounting device) packages
      2.2
      1.06 MB
      PDF
      TN1224

      Mounting instructions for SMD (surface mounting device) packages

Publications and Collaterals

    • Description Version Size Action
      Electric vehicle (EV) ecosystem 1.1
      1.28 MB
      PDF

      Electric vehicle (EV) ecosystem

Quality and Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
ST1S31D-R
NRND
SO-8 Industrial Ecopack2
ST1S31PUR
Active
VFDFPN 8 3x3x1.0 Industrial Ecopack2

ST1S31D-R

Package:

SO-8

Material Declaration**:

Marketing Status

NRND

Package

SO-8

Grade

Industrial

RoHS Compliance Grade

Ecopack2

ST1S31PUR

Package:

VFDFPN 8 3x3x1.0

Material Declaration**:

PDF XML

Marketing Status

Active

Package

VFDFPN 8 3x3x1.0

Grade

Industrial

RoHS Compliance Grade

Ecopack2

(**) 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.

eDesignSuite

Converter

Input

V This option is required. And must be less than or equal to Volt. Max [V]
V This option is required. And must be greater than or equal to Volt. Min [V]

Output Power

V This option is required and must be a number.
A This option is required and must be a number.

Sample & Buy

Part Number
Order from Distributors
Order from ST
Package
Packing Type
Marketing Status
ECCN (US)
Country of Origin
Budgetary Price (US$)*/Qty
ST1S31D-R Available at 2 distributors

Distributor availability ofST1S31D-R

Distributor Name
Region Stock Min. Order Third party link
RS COMPONENTS EUROPE 2545 1 Order Now
MOUSER WORLDWIDE 68 1 Order Now

Distributor reported inventory date: 2020-06-29

Distributor Name

RS COMPONENTS

Stock

2545

Min.Order

1

Region

EUROPE Order Now

MOUSER

Stock

68

Min.Order

1

Region

WORLDWIDE Order Now

Distributor reported inventory date: 2020-06-29

Buy now SO-8 Tape And Reel
NRND
EAR99 CHINA 0.471 / 1k
ST1S31PUR Available at 4 distributors

Distributor availability ofST1S31PUR

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 2675 1 Order Now
RS COMPONENTS EUROPE 790 1 Order Now
MOUSER WORLDWIDE 2379 1 Order Now
Farnell Element14 EUROPE 847 1 Order Now

Distributor reported inventory date: 2020-06-29

Distributor Name

DIGIKEY

Stock

2675

Min.Order

1

Region

WORLDWIDE Order Now

RS COMPONENTS

Stock

790

Min.Order

1

Region

EUROPE Order Now

MOUSER

Stock

2379

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

847

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-06-29

Get sample VFDFPN 8 3x3x1.0 Tape And Reel
Active
EAR99 MALAYSIA 0.535 / 1k

ST1S31D-R

Package

SO-8

Packing Type

Tape And Reel

Budgetary Price (US$)*/Qty

0.471 / 1k

Distributor availability ofST1S31D-R

Distributor Name
Region Stock Min. Order Third party link
RS COMPONENTS EUROPE 2545 1 Order Now
MOUSER WORLDWIDE 68 1 Order Now

Distributor reported inventory date: 2020-06-29

Distributor Name

RS COMPONENTS

Stock

2545

Min.Order

1

Region

EUROPE Order Now

MOUSER

Stock

68

Min.Order

1

Region

WORLDWIDE Order Now

Distributor reported inventory date: 2020-06-29

Marketing Status

NRND

Budgetary Price (US$)* / Qty

0.471 / 1k

ECCN (US)

EAR99

Country of Origin

CHINA

ST1S31PUR

Package

VFDFPN 8 3x3x1.0

Packing Type

Tape And Reel

Budgetary Price (US$)*/Qty

0.535 / 1k

Distributor availability ofST1S31PUR

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 2675 1 Order Now
RS COMPONENTS EUROPE 790 1 Order Now
MOUSER WORLDWIDE 2379 1 Order Now
Farnell Element14 EUROPE 847 1 Order Now

Distributor reported inventory date: 2020-06-29

Distributor Name

DIGIKEY

Stock

2675

Min.Order

1

Region

WORLDWIDE Order Now

RS COMPONENTS

Stock

790

Min.Order

1

Region

EUROPE Order Now

MOUSER

Stock

2379

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

847

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-06-29

Marketing Status

Active

Budgetary Price (US$)* / Qty

0.535 / 1k

ECCN (US)

EAR99

Country of Origin

MALAYSIA

(*) 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