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L5970D

May 2003

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UP TO 1A OUTPUT CURRENT

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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

1.2V 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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SINCHRONIZATION

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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 L5970D is a step down monolithic power

switching regulator capable to deliver up to 1A at

output voltages from 1.2V to 35V.

The device uses an internal P-Channel D-MOS

transistor (with a typical Rdson of 250m

Ω) as

switching element to minimize the size of the ex-

ternal components.

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

computer related applications.

Pulse by pulse current limit with the internal fre-

quency modulation offers an effective constant

current short circuit protection.

SO8

ORDERING NUMBERS: L5970D (SO8)

L5970D013TR (T&R)

UP TO 1A STEP DOWN SWITCHING REGULATOR

TEST APPLICATION CIRCUIT

D98IN954C

8

2

4

5

1

7

L5970D

C1

10

µF

35V

CERAMIC

C2

100

µF

10V

VOUT=3.3V

VIN = 4.4V to 35V

R1

5.6K

R2

3.3K

R3

4.7K

C4

22nF

C3

220pF

3

6

D1

STPS2L40U

3.3V

INH.

SYNC.

COMP

VCC

VREF

OUT

FB

GND

L1 33

µH