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L5973D

May 2003

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2.5A INTERNAL SWITCH

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OPERATING INPUT VOLTAGE FROM 4.4V TO 36V

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3.3V / (

±2%) REFERENCE VOLTAGE

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OUTPUT VOLTAGE ADJUSTABLE FROM

1.235V TO 35V

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LOW DROPOUT OPERATION: 100% DUTY

CYCLE

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250KHz INTERNALLY FIXED FREQUENCY

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VOLTAGE FEEDFORWARD

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ZERO LOAD CURRENT OPERATION

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INTERNAL CURRENT LIMITING

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INHIBIT FOR ZERO CURRENT

CONSUMPTION

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SYNCHRONIZATION

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PROTECTION AGAINST FEEDBACK

DISCONNECTION

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THERMAL SHUTDOWN

APPLICATIONS:

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CONSUMER: STB, DVD, TV, VCR,CAR

RADIO, LCD MONITORS

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NETWORKING: XDSL, MODEMS,DC-DC

MODULES

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COMPUTER: PRINTERS, AUDIO/GRAPHIC

CARDS, OPTICAL STORAGE, HARD DISK

DRIVE

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INDUSTRIAL: CHARGERS, CAR BATTERY

DC-DC CONVERTERS

DESCRIPTION

The L5973D is a step down monolithic power switch-

ing regulator with a minimum switch current limit of

2.5A so it is able to deliver more than 2A DC current

to the load depending on the application conditions.

The output voltage can be set from 1.235V to 35V.

The high current level is also achieved thanks to an

SO8 package with exposed frame, that allows to re-

The device uses an internal P-Channel D-MOS tran-

sistor (with a typical Rdson of 250m

Ω) as switching

element to minimize the size of the external compo-

nents.

An internal oscillator fixes the switching frequency at

250KHz.

Having a minimum input voltage of 4.4V only, it is

particularly suitable for 5V bus, available in all com-

puter related applications.

Pulse by pulse current limit with the internal frequen-

cy modulation offers an effective constant current

short circuit protection.

HSOP8 - EXPOSED PAD

ORDERING NUMBER: L5973D

2.5A SWITCH STEP DOWN SWITCHING REGULATOR

TEST APPLICATION CIRCUIT

D03IN1439

8

4

5

1

7

L5973D

C1

10

µF

35V

CERAMIC

C2

330

µF

10V

VOUT=3.3V

VIN = 4.4V to 35V

R1

5.6K

R2

3.3K

R3

4.7K

C4

22nF

C3

220pF

3

L1 15

µH

D1

STPS340U

COMP

VCC

OUT

FB

GND

INH

2

6

3.3V

SYNC.

VREF