1/9

August 2002

s

CONVERTS +4.0V TO + 6.2V INPUT TO -5V

OUTPUT

s

1W GUARANTEED OUTPUT POWER

s

75% TYPICAL EFFICIENCY

s

0.8mA QUIESCENT CURRENT

s

10µA SHUTDOWN MODE

s

160KHZ FIXED FREQUENCY OSCILLATOR

s

CURRENT MODE PWM CONVERTER

s

LOW NOISE AND JITTER

s

SOFT START

s

SIMPLE APPLICATION CIRCUIT

s

UNDERVOLTAGE LOCKOUT

DESCRIPTION

The ST735 is a Bi-CMOS, inverting switch mode

DC-DC regulator with internal Power MOSFET's

that generates a fixed -5V output voltage from a

4V to 6.2V input voltage; is guaranteed an output

current of 200mA for inputs greater than 4.5V. The

quiescent current for this device is typically of

0.8mA and, in shutdown mode it is reduced to

10µA.

These power-conserving features, along with high

efficiency and applications circuits, that lend itself

to minaturization, make the ST735 excellent in a

broad range of on-card, HDD and portable

equipment

applications. The ST735 employ a

high

performance

current

mode

pulse

with

modulation (PWM) control scheme to provide tight

output

voltage regulation and low

noise. The

fixed frequency oscillator is factory trimmed to

160KHz, allowing for easy noise filtering. The

regulator in production is tested to guarantee an

output accuracy within ±5% over all specified

conditions.

ST735

-5V INVERTING, NEGATIVE OUTPUT

CURRENT-MODE PWM REGULATOR

SCHEMATIC DIAGRAM

DIP-8

SO-8