ST735S Datasheet, PDF (1/11 Pages) STMicroelectronics – 300kHz, -5V/ADJ INVERTING, NEGATIVE OUTPUT CURRENT-MODE PWM REGULATOR

ST735S
ST735T
300kHz, -5V/ADJ INVERTING, NEGATIVE OUTPUT
CURRENT-MODE PWM REGULATOR
s CONVERTS +4.0V TO + 6.2V INPUT TO -5V
OUTPUT (735S) OR +3.5V TO + 9.0V TO A
NEGATIVE ADJUSTABLE OUTPUT (735T)
s 1W GUARANTEED OUTPUT POWER
s 72% TYPICAL EFFICIENCY
s 0.8mA QUIESCENT CURRENT
s 1µA SHUTDOWN MODE
s 300KHZ FIXED FREQUENCY OSCILLATOR
s CURRENT MODE PWM CONVERTER
s LOW NOISE AND JITTER
s SOFT START
s SIMPLE APPLICATION CIRCUIT
s UNDERVOLTAGE LOCKOUT (735S)
DESCRIPTION
The ST735S/ST735T is a Bi-CMOS, inverting
switch mode DC-DC regulator with internal Power
MOSFET that generates a fixed -5V (S version) or
a negative adjustable (T version) output voltage
from a 4V (3.5V for the 735T) to 6.2V input voltage
(9V for the 735T); is guaranteed an output current
of 200mA for inputs greater than 4.5V. The
quiescent current for this device is typically of
SCHEMATIC DIAGRAM
DIP-8
SO-8
0.8mA and, in shutdown mode it is reduced to
1µA.
These power-conserving features, along with high
efficiency and applications circuits, thaT lend itself
to minaturization, make the ST735S/ST735T
excellent in a broad range of on-card, HDD and
portable equipment applications. These device
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
300KHz, allowing for easy noise filtering. The
regulator in production is tested to guarantee an
output accuracy within ±5% over all specified
conditions.
October 2002
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