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L5970AD

March 2005

1

General Features

±2%) REFERENCE VOLTAGE

1.235V TO 35V

CYCLE

CONSUMPTION

DISCONNECTION

1.1 APPLICATIONS:

RADIO, LCD MONITORS

MODULES

CARDS, OPTICAL STORAGE, HARD DISK

DRIVE

DC-DC CONVERTERS

2

Description

The L5970AD is a step down monolithic power

switching regulator with a switch current limit of 1.5A

so it is able to deliver more than 1A DC current to the

load depending on the application conditions.

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

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

Ω) as switching

element to avoid the use of bootstrap capacitor and

guarantee high efficiency.

An internal oscillator fixes the switching frequency at

500KHz to minimize the size of external components.

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.

1.5A SWITCH STEP DOWN SWITCHING REGULATOR

Figure 2. Test and Application Circuit

D05IN1530

8

4

5

1

7

L5970AD

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

STPS2L25U

COMP

VCC

OUT

FB

GND

INH

2

6

3.3V

SYNC.

VREF

Figure 1. Package

Table 1. Order Codes

Part Number

Package

L5970AD

SO-8

L5970ADTR

SO-8 in Tape & Reel

SO-8

Rev. 1