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  • 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

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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

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
Marketing Status
ECCN (US)
ECCN (EU)
Packing Type
Package
Temperature (°C) Country of Origin
Budgetary Price (US$)*/Qty
min
max
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 302 1 Order Now
ARROW EUROPE 1000 0 Order Now
MOUSER WORLDWIDE 1183 1 Order Now
Farnell Element14 EUROPE 135 1 Order Now

Distributor reported inventory date: 2020-10-26

Distributor Name

DIGIKEY

Stock

960

Min.Order

1

Region

WORLDWIDE Order Now

RS COMPONENTS

Stock

302

Min.Order

1

Region

EUROPE Order Now

ARROW

Stock

1000

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

1183

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

135

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-10-26

Buy Direct
Active
EAR99 NEC Tube SO-20 - - MALAYSIA 1.811 / 1k
L4973D5.1-013TR Available at 3 distributors

Distributor availability ofL4973D5.1-013TR

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 817 1 Order Now
MOUSER WORLDWIDE 28 1 Order Now
ANGLIA Live EUROPE 23145 1 Order Now

Distributor reported inventory date: 2020-10-26

Distributor Name

DIGIKEY

Stock

817

Min.Order

1

Region

WORLDWIDE Order Now

MOUSER

Stock

28

Min.Order

1

Region

WORLDWIDE Order Now

ANGLIA Live

Stock

23145

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-10-26

Buy Direct
Active
EAR99 NEC Tape And Reel SO-20 - - 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 1575 0 Order Now
MOUSER WORLDWIDE 736 1 Order Now
Farnell Element14 EUROPE 998 1 Order Now

Distributor reported inventory date: 2020-10-26

Distributor Name

DIGIKEY

Stock

911

Min.Order

1

Region

WORLDWIDE Order Now

ARROW

Stock

1575

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

736

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

998

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-10-26

Free Sample Buy Direct
Active
EAR99 NEC Tube PDIP 18 - - MALAYSIA 1.693 / 1k
L4973D3.3-013TR Available at 4 distributors

Distributor availability ofL4973D3.3-013TR

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 981 1 Order Now
FUTURE WORLDWIDE 3000 1000 Order Now
ARROW EUROPE 3000 0 Order Now
MOUSER WORLDWIDE 449 1 Order Now

Distributor reported inventory date: 2020-10-26

Distributor Name

DIGIKEY

Stock

981

Min.Order

1

Region

WORLDWIDE Order Now

FUTURE

Stock

3000

Min.Order

1000

Region

WORLDWIDE Order Now

ARROW

Stock

3000

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

449

Min.Order

1

Region

WORLDWIDE Order Now

Distributor reported inventory date: 2020-10-26

Buy Direct
Active
EAR99 NEC Tape And Reel SO-20 - - 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 231 1 Order Now
ARROW EUROPE 1012 0 Order Now
MOUSER WORLDWIDE 718 1 Order Now
Farnell Element14 EUROPE 245 1 Order Now
ANGLIA Live EUROPE 307 1 Order Now

Distributor reported inventory date: 2020-10-26

Distributor Name

RS COMPONENTS

Stock

231

Min.Order

1

Region

EUROPE Order Now

ARROW

Stock

1012

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

718

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

245

Min.Order

1

Region

EUROPE Order Now

ANGLIA Live

Stock

307

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-10-26

Buy Direct
Active
EAR99 NEC Tube SO-20 - - 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 659 1 Order Now
RS COMPONENTS EUROPE 274 1 Order Now
ARROW EUROPE 122 0 Order Now
Newark Element14 AMERICA 3 0 Order Now
MOUSER WORLDWIDE 1421 1 Order Now
Farnell Element14 EUROPE 200 1 Order Now
ANGLIA Live EUROPE 1400 20 Order Now

Distributor reported inventory date: 2020-10-26

Distributor Name

DIGIKEY

Stock

659

Min.Order

1

Region

WORLDWIDE Order Now

RS COMPONENTS

Stock

274

Min.Order

1

Region

EUROPE Order Now

ARROW

Stock

122

Min.Order

0

Region

EUROPE Order Now

Newark Element14

Stock

3

Min.Order

0

Region

AMERICA Order Now

MOUSER

Stock

1421

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

200

Min.Order

1

Region

EUROPE Order Now

ANGLIA Live

Stock

1400

Min.Order

20

Region

EUROPE Order Now

Distributor reported inventory date: 2020-10-26

Free Sample Buy Direct
Active
EAR99 NEC Tube PDIP 18 - - MALAYSIA 1.778 / 1k

L4973D3.3

Marketing Status

Active

ECCN (US)

EAR99

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 302 1 Order Now
ARROW EUROPE 1000 0 Order Now
MOUSER WORLDWIDE 1183 1 Order Now
Farnell Element14 EUROPE 135 1 Order Now

Distributor reported inventory date: 2020-10-26

Distributor Name

DIGIKEY

Stock

960

Min.Order

1

Region

WORLDWIDE Order Now

RS COMPONENTS

Stock

302

Min.Order

1

Region

EUROPE Order Now

ARROW

Stock

1000

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

1183

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

135

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-10-26

ECCN (EU)

NEC

Packing Type

Tube

Package

SO-20

Operating Temperature (°C)

(min)

-

(max)

-

Budgetary Price (US$)* / Qty

1.811 / 1k

Country of Origin

MALAYSIA

L4973D5.1-013TR

Marketing Status

Active

ECCN (US)

EAR99

Budgetary Price (US$)*/Qty

1.861 / 1k

Distributor availability ofL4973D5.1-013TR

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 817 1 Order Now
MOUSER WORLDWIDE 28 1 Order Now
ANGLIA Live EUROPE 23145 1 Order Now

Distributor reported inventory date: 2020-10-26

Distributor Name

DIGIKEY

Stock

817

Min.Order

1

Region

WORLDWIDE Order Now

MOUSER

Stock

28

Min.Order

1

Region

WORLDWIDE Order Now

ANGLIA Live

Stock

23145

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-10-26

ECCN (EU)

NEC

Packing Type

Tape And Reel

Package

SO-20

Operating Temperature (°C)

(min)

-

(max)

-

Budgetary Price (US$)* / Qty

1.861 / 1k

Country of Origin

MALAYSIA

L4973V3.3

Marketing Status

Active

ECCN (US)

EAR99

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 1575 0 Order Now
MOUSER WORLDWIDE 736 1 Order Now
Farnell Element14 EUROPE 998 1 Order Now

Distributor reported inventory date: 2020-10-26

Distributor Name

DIGIKEY

Stock

911

Min.Order

1

Region

WORLDWIDE Order Now

ARROW

Stock

1575

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

736

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

998

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-10-26

ECCN (EU)

NEC

Packing Type

Tube

Package

PDIP 18

Operating Temperature (°C)

(min)

-

(max)

-

Budgetary Price (US$)* / Qty

1.693 / 1k

Country of Origin

MALAYSIA

L4973D3.3-013TR

Marketing Status

Active

ECCN (US)

EAR99

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 3000 1000 Order Now
ARROW EUROPE 3000 0 Order Now
MOUSER WORLDWIDE 449 1 Order Now

Distributor reported inventory date: 2020-10-26

Distributor Name

DIGIKEY

Stock

981

Min.Order

1

Region

WORLDWIDE Order Now

FUTURE

Stock

3000

Min.Order

1000

Region

WORLDWIDE Order Now

ARROW

Stock

3000

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

449

Min.Order

1

Region

WORLDWIDE Order Now

Distributor reported inventory date: 2020-10-26

ECCN (EU)

NEC

Packing Type

Tape And Reel

Package

SO-20

Operating Temperature (°C)

(min)

-

(max)

-

Budgetary Price (US$)* / Qty

1.811 / 1k

Country of Origin

MALAYSIA

L4973D5.1

Marketing Status

Active

ECCN (US)

EAR99

Budgetary Price (US$)*/Qty

1.861 / 1k

Distributor availability ofL4973D5.1

Distributor Name
Region Stock Min. Order Third party link
RS COMPONENTS EUROPE 231 1 Order Now
ARROW EUROPE 1012 0 Order Now
MOUSER WORLDWIDE 718 1 Order Now
Farnell Element14 EUROPE 245 1 Order Now
ANGLIA Live EUROPE 307 1 Order Now

Distributor reported inventory date: 2020-10-26

Distributor Name

RS COMPONENTS

Stock

231

Min.Order

1

Region

EUROPE Order Now

ARROW

Stock

1012

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

718

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

245

Min.Order

1

Region

EUROPE Order Now

ANGLIA Live

Stock

307

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2020-10-26

ECCN (EU)

NEC

Packing Type

Tube

Package

SO-20

Operating Temperature (°C)

(min)

-

(max)

-

Budgetary Price (US$)* / Qty

1.861 / 1k

Country of Origin

MALAYSIA

L4973V5.1

Marketing Status

Active

ECCN (US)

EAR99

Budgetary Price (US$)*/Qty

1.778 / 1k

Distributor availability ofL4973V5.1

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 659 1 Order Now
RS COMPONENTS EUROPE 274 1 Order Now
ARROW EUROPE 122 0 Order Now
Newark Element14 AMERICA 3 0 Order Now
MOUSER WORLDWIDE 1421 1 Order Now
Farnell Element14 EUROPE 200 1 Order Now
ANGLIA Live EUROPE 1400 20 Order Now

Distributor reported inventory date: 2020-10-26

Distributor Name

DIGIKEY

Stock

659

Min.Order

1

Region

WORLDWIDE Order Now

RS COMPONENTS

Stock

274

Min.Order

1

Region

EUROPE Order Now

ARROW

Stock

122

Min.Order

0

Region

EUROPE Order Now

Newark Element14

Stock

3

Min.Order

0

Region

AMERICA Order Now

MOUSER

Stock

1421

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

200

Min.Order

1

Region

EUROPE Order Now

ANGLIA Live

Stock

1400

Min.Order

20

Region

EUROPE Order Now

Distributor reported inventory date: 2020-10-26

ECCN (EU)

NEC

Packing Type

Tube

Package

PDIP 18

Operating Temperature (°C)

(min)

-

(max)

-

Budgetary Price (US$)* / Qty

1.778 / 1k

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