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  • The L9409 is a monolithic multifunction alternator voltage regulator intended for use in automotive applications.

    The device regulates the output of an automotive generator by controlling the field winding current by means of either an analog fixed frequency PWM signal or digital fixed frequency PWM signal (LRC). The Load Response Control function is activated in order to eliminate IC engine speed fluctuation and vibrations caused by the insertion of sudden electrical loads during alternator low speed operations (f < 310 Hz). Both the analog and digital duty cycle are applied to a high side driver.
    The device is able to regulate the voltage either using a feedback signal from B pin or from S pin depending on application needs. S pin is intended to have a clear direct connection with the positive terminal of the car battery. If this connection gets lost the device will regulate voltage using B pin giving a fail safe functionality.
    Using L pin is possible to sense key switch and a pre-excitation duty cycle is applied on the field coil in order to start phase voltage sensing. In the case L connection gets lost, device starts to generate using residual magnetism of the generator.
    Field, lamp and relay drivers are protected against short circuit.

    Key Features

    • IC regulator for 12 V type alternator
    • Fixed frequency regulation loop
    • 130 mΩ high side field driver
    • Fail safe device with double sensing of battery voltage (VB and VS)
    • Load response control (LRC) function activates after an initial time delay
    • Self start function from phase frequency
    • “Z” shaped regulation curve compliant with VW specification.
    • Key recognition from L input
    • Field driver, lamp driver and relay driver short protection
    • Complex diagnostics
    • Thermal shutdown at 175 °C

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Technical Documentation

    • Description Version Size Action
      DS8833
      Alternator voltage regulator with load response control
      2.0
      161.95 KB
      PDF
      DS8833

      Alternator voltage regulator with load response control

Quality and Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
L9409F
Active
MW 8L Automotive Ecopack1

L9409F

Package:

MW 8L

Material Declaration**:

Marketing Status

Active

Package

MW 8L

Grade

Automotive

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

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ECCN (US)
ECCN (EU)
Packing Type
Package
Temperature (°C) Country of Origin
Budgetary Price (US$)*/Qty
min
max
L9409F Available at 3 distributors

Distributor availability ofL9409F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 500 1 Order Now
MOUSER WORLDWIDE 485 1 Order Now
RUTRONIK EUROPE 8250 25 Order Now

Distributor reported inventory date: 2020-08-04

Distributor Name

DIGIKEY

Stock

500

Min.Order

1

Region

WORLDWIDE Order Now

MOUSER

Stock

485

Min.Order

1

Region

WORLDWIDE Order Now

RUTRONIK

Stock

8250

Min.Order

25

Region

EUROPE Order Now

Distributor reported inventory date: 2020-08-04

Buy now
Active
EAR99 NEC Tube MW 8L -40 150 MOROCCO 3.9 / 1k

L9409F

Marketing Status

Active

ECCN (US)

EAR99

Budgetary Price (US$)*/Qty

3.9 / 1k

Distributor availability ofL9409F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 500 1 Order Now
MOUSER WORLDWIDE 485 1 Order Now
RUTRONIK EUROPE 8250 25 Order Now

Distributor reported inventory date: 2020-08-04

Distributor Name

DIGIKEY

Stock

500

Min.Order

1

Region

WORLDWIDE Order Now

MOUSER

Stock

485

Min.Order

1

Region

WORLDWIDE Order Now

RUTRONIK

Stock

8250

Min.Order

25

Region

EUROPE Order Now

Distributor reported inventory date: 2020-08-04

ECCN (EU)

NEC

Packing Type

Tube

Package

MW 8L

Operating Temperature (°C)

(min)

-40

(max)

150

Budgetary Price (US$)* / Qty

3.9 / 1k

Country of Origin

MOROCCO

(*) 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