Overview
Sample & Buy
Solutions
Resources
Tools & Software
Quality & Reliability
eDesignSuite
Get Started
Partner products
Sales Briefcase
  • The L4973 is a step down monolithic power switching regulator delivering 3.5A at fixed voltages of 3.3V or 5.1V and using a simple external divider output adjustable voltage up to 50V. Realized in BCD mixed technology, the device uses an internal power D-MOS transistor (with a typical RDS(on) of 0.15Ω) to obtain very high efficiency and very fast switching times. Switching frequency up to 300KHz are achievable (the maximum power dissipation of the packages must be observed).

    A wide input voltage range between 8V to 55V and output voltages regulated from 3.3V to 40V cover the majority of the today applications. Features of this new generation of DC-DC converter includes pulse by pulse current limit, hiccup mode for output short circuit protection, voltage feed forward regulation, soft start, input/output synchronization, protection against feedback loop disconnection, inhibit for zero current consumption and thermal shutdown. Packages available are in plastic dual in line, DIP- 18 (12+3+3) for standard assembly, and SO20 (12+4+4) for SMD assembly.

    Key Features

    • Inhibit for zero current consumption (100mA at VCC= 24V)
    • Input/output synchronization function
    • Thermal shutdown
    • Protection against feedback disconnection
    • Soft start function
    • Output over voltage protection
    • Internal current limiting (pulse by pulse and HICCUP mode)
    • Zero load current operation (min 1mA)
    • Up to 3.5A step down converter
    • 3.3V and 5.1V (±1%) fixed output, and adjustable outputs from: 0.5V to 50V (3.3 type)5.1V to 50V (5.1 type)
    • Operating input voltage from 8V to 55V
    • Voltage feed forward
    • Precise 5.1V (1.5%) reference voltage externally available
    • Frequency adjustable up to 300kHz

Circuit Diagram

Download Download

Recommended for you

Related Applications

Smart Farming

00 Files selected for download

Technical Documentation

    • Description Version Size Action
      DS0169
      3.5 A step down switching regulator
      18.2
      635.57 KB
      PDF
      DS0169

      3.5 A step down switching regulator

    • Description Version Size Action
      AN1126
      Current sharing of the L4973 in a multiphase application
      1.2
      191.75 KB
      PDF
      AN938
      Designing with L4973, 3.5 A high efficiency DC-DC converter
      10.1
      1.7 MB
      PDF
      AN1126

      Current sharing of the L4973 in a multiphase application

      AN938

      Designing with L4973, 3.5 A high efficiency DC-DC converter

    • 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

    • Description Version Size Action
      DN0011
      ST1S03 alternative topology: Using a buck in a negative buck-boost configuration
      1.2
      361.3 KB
      PDF
      DN0011

      ST1S03 alternative topology: Using a buck in a negative buck-boost configuration

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**
L4973D3.3
Active
SO-20 Industrial Ecopack2
L4973D3.3-013TR
Active
SO-20 Industrial Ecopack1 (*)
L4973D5.1
Active
SO-20 Industrial Ecopack2
L4973D5.1-013TR
Active
SO-20 Industrial Ecopack2
L4973V3.3
Active
PDIP 18 Industrial Ecopack1
L4973V5.1
Active
PDIP 18 Industrial Ecopack1

L4973D3.3

Package:

SO-20

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO-20

Grade

Industrial

RoHS Compliance Grade

Ecopack2

L4973D3.3-013TR

Package:

SO-20

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO-20

Grade

Industrial

RoHS Compliance Grade

Ecopack1 (*)

L4973D5.1

Package:

SO-20

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO-20

Grade

Industrial

RoHS Compliance Grade

Ecopack2

L4973D5.1-013TR

Package:

SO-20

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO-20

Grade

Industrial

RoHS Compliance Grade

Ecopack2

L4973V3.3

Package:

PDIP 18

Material Declaration**:

PDF XML

Marketing Status

Active

Package

PDIP 18

Grade

Industrial

RoHS Compliance Grade

Ecopack1

L4973V5.1

Package:

PDIP 18

Material Declaration**:

PDF XML

Marketing Status

Active

Package

PDIP 18

Grade

Industrial

RoHS Compliance Grade

Ecopack1

(**) 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
L4973D3.3 Available at 5 distributors

Distributor availability ofL4973D3.3

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 960 1 Order Now
RS COMPONENTS EUROPE 132 1 Order Now
ARROW EUROPE 1000 0 Order Now
MOUSER WORLDWIDE 1210 1 Order Now
Farnell Element14 EUROPE 190 1 Order Now

Distributor reported inventory date: 2020-07-12

Distributor Name

DIGIKEY

Stock

960

Min.Order

1

Region

WORLDWIDE Order Now

RS COMPONENTS

Stock

132

Min.Order

1

Region

EUROPE Order Now

ARROW

Stock

1000

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

1210

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

190

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-07-12

Buy now SO-20 Tube
Active
EAR99 MALAYSIA 1.811 / 1k
L4973D5.1-013TR Available at 5 distributors

Distributor availability ofL4973D5.1-013TR

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 835 1 Order Now
ARROW EUROPE 2000 0 Order Now
ARROW AMERICA 2000 1000 Order Now
MOUSER WORLDWIDE 29 1 Order Now
ANGLIA Live EUROPE 23145 1 Order Now

Distributor reported inventory date: 2020-07-12

Distributor Name

DIGIKEY

Stock

835

Min.Order

1

Region

WORLDWIDE Order Now

ARROW

Stock

2000

Min.Order

0

Region

EUROPE Order Now

ARROW

Stock

2000

Min.Order

1000

Region

AMERICA Order Now

MOUSER

Stock

29

Min.Order

1

Region

WORLDWIDE Order Now

ANGLIA Live

Stock

23145

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-07-12

Buy now SO-20 Tape And Reel
Active
EAR99 MALAYSIA 1.861 / 1k
L4973V3.3 Available at 4 distributors

Distributor availability ofL4973V3.3

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 911 1 Order Now
ARROW EUROPE 2000 0 Order Now
MOUSER WORLDWIDE 743 1 Order Now
Farnell Element14 EUROPE 1000 1 Order Now

Distributor reported inventory date: 2020-07-12

Distributor Name

DIGIKEY

Stock

911

Min.Order

1

Region

WORLDWIDE Order Now

ARROW

Stock

2000

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

743

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

1000

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-07-12

Get sample PDIP 18 Tube
Active
EAR99 MALAYSIA 1.693 / 1k
L4973D3.3-013TR Available at 5 distributors

Distributor availability ofL4973D3.3-013TR

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 981 1 Order Now
FUTURE WORLDWIDE 4000 1000 Order Now
ARROW EUROPE 1000 0 Order Now
ARROW AMERICA 2000 1000 Order Now
MOUSER WORLDWIDE 451 1 Order Now

Distributor reported inventory date: 2020-07-12

Distributor Name

DIGIKEY

Stock

981

Min.Order

1

Region

WORLDWIDE Order Now

FUTURE

Stock

4000

Min.Order

1000

Region

WORLDWIDE Order Now

ARROW

Stock

1000

Min.Order

0

Region

EUROPE Order Now

ARROW

Stock

2000

Min.Order

1000

Region

AMERICA Order Now

MOUSER

Stock

451

Min.Order

1

Region

WORLDWIDE Order Now

Distributor reported inventory date: 2020-07-12

Buy now SO-20 Tape And Reel
Active
EAR99 MALAYSIA 1.811 / 1k
L4973D5.1 Available at 5 distributors

Distributor availability ofL4973D5.1

Distributor Name
Region Stock Min. Order Third party link
RS COMPONENTS EUROPE 54 1 Order Now
ARROW EUROPE 212 0 Order Now
MOUSER WORLDWIDE 831 1 Order Now
Farnell Element14 EUROPE 361 1 Order Now
ANGLIA Live EUROPE 307 1 Order Now

Distributor reported inventory date: 2020-07-12

Distributor Name

RS COMPONENTS

Stock

54

Min.Order

1

Region

EUROPE Order Now

ARROW

Stock

212

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

831

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

361

Min.Order

1

Region

EUROPE Order Now

ANGLIA Live

Stock

307

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-07-12

Buy now SO-20 Tube
Active
EAR99 MALAYSIA 1.861 / 1k
L4973V5.1 Available at 7 distributors

Distributor availability ofL4973V5.1

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 747 1 Order Now
RS COMPONENTS EUROPE 268 1 Order Now
ARROW EUROPE 250 0 Order Now
Newark Element14 AMERICA 3 0 Order Now
MOUSER WORLDWIDE 1465 1 Order Now
Farnell Element14 EUROPE 225 1 Order Now
ANGLIA Live EUROPE 1600 20 Order Now

Distributor reported inventory date: 2020-07-12

Distributor Name

DIGIKEY

Stock

747

Min.Order

1

Region

WORLDWIDE Order Now

RS COMPONENTS

Stock

268

Min.Order

1

Region

EUROPE Order Now

ARROW

Stock

250

Min.Order

0

Region

EUROPE Order Now

Newark Element14

Stock

3

Min.Order

0

Region

AMERICA Order Now

MOUSER

Stock

1465

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

225

Min.Order

1

Region

EUROPE Order Now

ANGLIA Live

Stock

1600

Min.Order

20

Region

EUROPE Order Now

Distributor reported inventory date: 2020-07-12

Get sample PDIP 18 Tube
Active
EAR99 MALAYSIA 1.778 / 1k

L4973D3.3

Package

SO-20

Packing Type

Tube

Budgetary Price (US$)*/Qty

1.811 / 1k

Distributor availability ofL4973D3.3

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 960 1 Order Now
RS COMPONENTS EUROPE 132 1 Order Now
ARROW EUROPE 1000 0 Order Now
MOUSER WORLDWIDE 1210 1 Order Now
Farnell Element14 EUROPE 190 1 Order Now

Distributor reported inventory date: 2020-07-12

Distributor Name

DIGIKEY

Stock

960

Min.Order

1

Region

WORLDWIDE Order Now

RS COMPONENTS

Stock

132

Min.Order

1

Region

EUROPE Order Now

ARROW

Stock

1000

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

1210

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

190

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-07-12

Marketing Status

Active

Budgetary Price (US$)* / Qty

1.811 / 1k

ECCN (US)

EAR99

Country of Origin

MALAYSIA

L4973D5.1-013TR

Package

SO-20

Packing Type

Tape And Reel

Budgetary Price (US$)*/Qty

1.861 / 1k

Distributor availability ofL4973D5.1-013TR

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 835 1 Order Now
ARROW EUROPE 2000 0 Order Now
ARROW AMERICA 2000 1000 Order Now
MOUSER WORLDWIDE 29 1 Order Now
ANGLIA Live EUROPE 23145 1 Order Now

Distributor reported inventory date: 2020-07-12

Distributor Name

DIGIKEY

Stock

835

Min.Order

1

Region

WORLDWIDE Order Now

ARROW

Stock

2000

Min.Order

0

Region

EUROPE Order Now

ARROW

Stock

2000

Min.Order

1000

Region

AMERICA Order Now

MOUSER

Stock

29

Min.Order

1

Region

WORLDWIDE Order Now

ANGLIA Live

Stock

23145

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-07-12

Marketing Status

Active

Budgetary Price (US$)* / Qty

1.861 / 1k

ECCN (US)

EAR99

Country of Origin

MALAYSIA

L4973V3.3

Package

PDIP 18

Packing Type

Tube

Budgetary Price (US$)*/Qty

1.693 / 1k

Distributor availability ofL4973V3.3

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 911 1 Order Now
ARROW EUROPE 2000 0 Order Now
MOUSER WORLDWIDE 743 1 Order Now
Farnell Element14 EUROPE 1000 1 Order Now

Distributor reported inventory date: 2020-07-12

Distributor Name

DIGIKEY

Stock

911

Min.Order

1

Region

WORLDWIDE Order Now

ARROW

Stock

2000

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

743

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

1000

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-07-12

Marketing Status

Active

Budgetary Price (US$)* / Qty

1.693 / 1k

ECCN (US)

EAR99

Country of Origin

MALAYSIA

L4973D3.3-013TR

Package

SO-20

Packing Type

Tape And Reel

Budgetary Price (US$)*/Qty

1.811 / 1k

Distributor availability ofL4973D3.3-013TR

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 981 1 Order Now
FUTURE WORLDWIDE 4000 1000 Order Now
ARROW EUROPE 1000 0 Order Now
ARROW AMERICA 2000 1000 Order Now
MOUSER WORLDWIDE 451 1 Order Now

Distributor reported inventory date: 2020-07-12

Distributor Name

DIGIKEY

Stock

981

Min.Order

1

Region

WORLDWIDE Order Now

FUTURE

Stock

4000

Min.Order

1000

Region

WORLDWIDE Order Now

ARROW

Stock

1000

Min.Order

0

Region

EUROPE Order Now

ARROW

Stock

2000

Min.Order

1000

Region

AMERICA Order Now

MOUSER

Stock

451

Min.Order

1

Region

WORLDWIDE Order Now

Distributor reported inventory date: 2020-07-12

Marketing Status

Active

Budgetary Price (US$)* / Qty

1.811 / 1k

ECCN (US)

EAR99

Country of Origin

MALAYSIA

L4973D5.1

Package

SO-20

Packing Type

Tube

Budgetary Price (US$)*/Qty

1.861 / 1k

Distributor availability ofL4973D5.1

Distributor Name
Region Stock Min. Order Third party link
RS COMPONENTS EUROPE 54 1 Order Now
ARROW EUROPE 212 0 Order Now
MOUSER WORLDWIDE 831 1 Order Now
Farnell Element14 EUROPE 361 1 Order Now
ANGLIA Live EUROPE 307 1 Order Now

Distributor reported inventory date: 2020-07-12

Distributor Name

RS COMPONENTS

Stock

54

Min.Order

1

Region

EUROPE Order Now

ARROW

Stock

212

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

831

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

361

Min.Order

1

Region

EUROPE Order Now

ANGLIA Live

Stock

307

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-07-12

Marketing Status

Active

Budgetary Price (US$)* / Qty

1.861 / 1k

ECCN (US)

EAR99

Country of Origin

MALAYSIA

L4973V5.1

Package

PDIP 18

Packing Type

Tube

Budgetary Price (US$)*/Qty

1.778 / 1k

Distributor availability ofL4973V5.1

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 747 1 Order Now
RS COMPONENTS EUROPE 268 1 Order Now
ARROW EUROPE 250 0 Order Now
Newark Element14 AMERICA 3 0 Order Now
MOUSER WORLDWIDE 1465 1 Order Now
Farnell Element14 EUROPE 225 1 Order Now
ANGLIA Live EUROPE 1600 20 Order Now

Distributor reported inventory date: 2020-07-12

Distributor Name

DIGIKEY

Stock

747

Min.Order

1

Region

WORLDWIDE Order Now

RS COMPONENTS

Stock

268

Min.Order

1

Region

EUROPE Order Now

ARROW

Stock

250

Min.Order

0

Region

EUROPE Order Now

Newark Element14

Stock

3

Min.Order

0

Region

AMERICA Order Now

MOUSER

Stock

1465

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

225

Min.Order

1

Region

EUROPE Order Now

ANGLIA Live

Stock

1600

Min.Order

20

Region

EUROPE Order Now

Distributor reported inventory date: 2020-07-12

Marketing Status

Active

Budgetary Price (US$)* / Qty

1.778 / 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