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January 2003

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UP TO 450mA LOAD CURRENTS

s

200kHz HIGH-FREQUENCY

CURRENT-MODE PWM

s

85% TO 96% EFFICIENCIES

s

33

µHOR100µH PRE-SELECTED

INDUCTOR VALUE, NO COMPONENT

DESIGN REQUIRED

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0.8mA QUIESCENT CURRENT

s

0.3µA SHUTDOWN SUPPLY CURRENT

s

ADJUSTABLE OUTPUT VOLTAGE

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OVERCURRENT, SOFT-START AND

UNDERVOLTAGE LOCKOUT PROTECTION

s

CYCLE-BY-CYCLE CURRENT LIMITING

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PACKAGE AVAILABLE : DIP- 8 AND SO - 8

DESCRIPTION

The ST750A is an adjustable output CMOS,

step-down

switching

regulator.

The

ST750A

accepts inputs between 4V and 11V and delivers

450mA. Typical efficiencies are 85% to 96%.

Quiescent supply current is 0.8mA and only 0.3

µA

in shutdown mode. The output does not exhibit

frequency over this specified range. Pulse-width

modulation (PWM) current-mode control provides

precise output regulation and excellent transient

responses.

Output

voltage

accuracy

is

guaranteed to be ±4.5% plus feedback resistor

tolerance

over

line,

load,

and

temperature

varations.

Fixed-frequency

switching

and

absence

of

subharmonic ruipple allows easy filtering of output

ripple and noise, as well as the use of small

external components. This regulators require only

a

single

inductor

value

to

work

in

most

applications, so no inductor design is necessary.

Typical applications are: Cellular phones & radios,

portable Instruments, Portable Communications

Equipments and Computer Peripherals.

ST750A

ADJUSTABLE STEP-DOWN,

CURRENT-MODE PWM DC-DC CONVERTERS

SCHEMATIC DIAGRAM

DIP-8

SO-8