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  • The L4978 is a step down monolithic power switching regulator delivering 2A at a voltage between 3.3V and 50V (selected by a simple external divider). Realized in BCD mixed technology, the device uses an internal power D-MOS transistor (with a typical Rdson of 0.25Ω) to obtain very high efficency and high switching speed.

    A switching frequency up to 300KHz is 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 50V cover the majority of today’s applications. Features of this new generations of DC-DC converter include pulse-by-pulse current limit, hiccup mode for short circuit protection, voltage feedforward regulation, soft-start, protection against feedback loop disconnection, inhibit for zero current consumption and thermal shutdown.
    The device is available in plastic dual in line, DIP-8 for standard assembly, and SO16W for SMD assembly.

    Key Features

    • PROTECTION AGAINST FEEDBACK DISCONNECTION
    • INHIBIT FOR ZERO CURRENT CONSUMPTION
    • SOFT START FUNCTION
    • THERMAL SHUTDOWN
    • ZERO LOAD CURRENT OPERATION
    • VOLTAGE FEEDFORWARD
    • UP TO 2A STEP DOWN CONVERTER
    • PRECISE 3.3V (±1%) INTERNAL REFERENCE VOLTAGE
    • OPERATING INPUT VOLTAGE FROM 8V TO 55V
    • SWITCHING FREQUENCY ADJUSTABLE UP TO 300KHz
    • INTERNAL CURRENT LIMITING (PULSE-BYPULSE AND HICCUP MODE)
    • OUTPUT VOLTAGE ADJUSTABLE FROM 3.3V TO 50V

Circuit Diagram

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Technical Documentation

    • Description Version Size Action
      DS1309
      2A step down switching regulator
      9.2
      578.46 KB
      PDF
      DS1309

      2A step down switching regulator

    • Description Version Size Action
      AN1061
      Designing with L4978, 2A high efficiency DC-DC convertery
      9.2
      793.18 KB
      PDF
      AN1061

      Designing with L4978, 2A high efficiency DC-DC convertery

    • 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**
L4978
Active
DIP-8 Industrial Ecopack2
L4978D
Active
SO-16W Industrial Ecopack1
L4978D013TR
Active
SO-16W Industrial Ecopack1

L4978

Package:

DIP-8

Material Declaration**:

Marketing Status

Active

Package

DIP-8

Grade

Industrial

RoHS Compliance Grade

Ecopack2

L4978D

Package:

SO-16W

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO-16W

Grade

Industrial

RoHS Compliance Grade

Ecopack1

L4978D013TR

Package:

SO-16W

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO-16W

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.

Sample & Buy

Part Number
Order from Distributors
Order from ST
Package
Packing Type
Marketing Status
ECCN (US)
Country of Origin
Budgetary Price (US$)*/Qty
L4978D013TR Available at 3 distributors

Distributor availability ofL4978D013TR

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 1508 1 Order Now
COMPEL EUROPE 3112 1 Order Now
MOUSER WORLDWIDE 3609 1 Order Now

Distributor reported inventory date: 2020-07-08

Distributor Name

DIGIKEY

Stock

1508

Min.Order

1

Region

WORLDWIDE Order Now

COMPEL

Stock

3112

Min.Order

1

Region

EUROPE Order Now

MOUSER

Stock

3609

Min.Order

1

Region

WORLDWIDE Order Now

Distributor reported inventory date: 2020-07-08

Get sample SO-16W Tape And Reel
Active
EAR99 MALAYSIA 1.389 / 1k
L4978 Available at 7 distributors

Distributor availability ofL4978

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 801 1 Order Now
COMPEL EUROPE 3403 1 Order Now
FUTURE WORLDWIDE 545 1 Order Now
ARROW EUROPE 335 0 Order Now
Newark Element14 AMERICA 97 0 Order Now
MOUSER WORLDWIDE 837 1 Order Now
Farnell Element14 EUROPE 909 1 Order Now

Distributor reported inventory date: 2020-07-08

Distributor Name

DIGIKEY

Stock

801

Min.Order

1

Region

WORLDWIDE Order Now

COMPEL

Stock

3403

Min.Order

1

Region

EUROPE Order Now

FUTURE

Stock

545

Min.Order

1

Region

WORLDWIDE Order Now

ARROW

Stock

335

Min.Order

0

Region

EUROPE Order Now

Newark Element14

Stock

97

Min.Order

0

Region

AMERICA Order Now

MOUSER

Stock

837

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

909

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-07-08

Get sample DIP-8 Tube
Active
EAR99 CHINA 1.389 / 1k
L4978D Available at 5 distributors

Distributor availability ofL4978D

Distributor Name
Region Stock Min. Order Third party link
RS COMPONENTS EUROPE 1324 1 Order Now
Newark Element14 AMERICA 487 0 Order Now
ARROW AMERICA 9 1225 Order Now
MOUSER WORLDWIDE 1944 1 Order Now
Farnell Element14 EUROPE 320 1 Order Now

Distributor reported inventory date: 2020-07-08

Distributor Name

RS COMPONENTS

Stock

1324

Min.Order

1

Region

EUROPE Order Now

Newark Element14

Stock

487

Min.Order

0

Region

AMERICA Order Now

ARROW

Stock

9

Min.Order

1225

Region

AMERICA Order Now

MOUSER

Stock

1944

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

320

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-07-08

Buy now SO-16W Tube
Active
EAR99 MALAYSIA 1.389 / 1k

L4978D013TR

Package

SO-16W

Packing Type

Tape And Reel

Budgetary Price (US$)*/Qty

1.389 / 1k

Distributor availability ofL4978D013TR

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 1508 1 Order Now
COMPEL EUROPE 3112 1 Order Now
MOUSER WORLDWIDE 3609 1 Order Now

Distributor reported inventory date: 2020-07-08

Distributor Name

DIGIKEY

Stock

1508

Min.Order

1

Region

WORLDWIDE Order Now

COMPEL

Stock

3112

Min.Order

1

Region

EUROPE Order Now

MOUSER

Stock

3609

Min.Order

1

Region

WORLDWIDE Order Now

Distributor reported inventory date: 2020-07-08

Marketing Status

Active

Budgetary Price (US$)* / Qty

1.389 / 1k

ECCN (US)

EAR99

Country of Origin

MALAYSIA

L4978

Package

DIP-8

Packing Type

Tube

Budgetary Price (US$)*/Qty

1.389 / 1k

Distributor availability ofL4978

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 801 1 Order Now
COMPEL EUROPE 3403 1 Order Now
FUTURE WORLDWIDE 545 1 Order Now
ARROW EUROPE 335 0 Order Now
Newark Element14 AMERICA 97 0 Order Now
MOUSER WORLDWIDE 837 1 Order Now
Farnell Element14 EUROPE 909 1 Order Now

Distributor reported inventory date: 2020-07-08

Distributor Name

DIGIKEY

Stock

801

Min.Order

1

Region

WORLDWIDE Order Now

COMPEL

Stock

3403

Min.Order

1

Region

EUROPE Order Now

FUTURE

Stock

545

Min.Order

1

Region

WORLDWIDE Order Now

ARROW

Stock

335

Min.Order

0

Region

EUROPE Order Now

Newark Element14

Stock

97

Min.Order

0

Region

AMERICA Order Now

MOUSER

Stock

837

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

909

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-07-08

Marketing Status

Active

Budgetary Price (US$)* / Qty

1.389 / 1k

ECCN (US)

EAR99

Country of Origin

CHINA

L4978D

Package

SO-16W

Packing Type

Tube

Budgetary Price (US$)*/Qty

1.389 / 1k

Distributor availability ofL4978D

Distributor Name
Region Stock Min. Order Third party link
RS COMPONENTS EUROPE 1324 1 Order Now
Newark Element14 AMERICA 487 0 Order Now
ARROW AMERICA 9 1225 Order Now
MOUSER WORLDWIDE 1944 1 Order Now
Farnell Element14 EUROPE 320 1 Order Now

Distributor reported inventory date: 2020-07-08

Distributor Name

RS COMPONENTS

Stock

1324

Min.Order

1

Region

EUROPE Order Now

Newark Element14

Stock

487

Min.Order

0

Region

AMERICA Order Now

ARROW

Stock

9

Min.Order

1225

Region

AMERICA Order Now

MOUSER

Stock

1944

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

320

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-07-08

Marketing Status

Active

Budgetary Price (US$)* / Qty

1.389 / 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