ST1534A Datasheet, PDF (1/15 Pages) STMicroelectronics – 500mA SMART LDO

ST1534A
500mA SMART LDO
s GLITCH FREE TRANSITION BETWEEN
INPUT SOURCES
s INTERNAL LOGIC SELECTS INPUT
SOURCE
s GATE DRIVE FOR EXTERNAL PMOS
BYPASS SWITCH
s 5V DETECTOR WITH HYSTERESIS
s 1% 3.3V REGULATED OUTPUT VOLTAGE
s 500mA GUARANTEED OUTPUT CURRENT
s OPERATING TEMPERATURE RANGE
FROM 0°C TO 85°C
s AVAILABLE IN P²PAK PACKAGE
s PPAK AND SO-8 PACKAGES CAN BE
AVAILABLE ON REQUEST
APPLICATIONS
s NETWORK INTERFACE CARDS
s PCMCIA/PCI INTERFACE CARDS
s DESKTOP COMPUTERS
s POWER SUPPLY WITH MULTIPLE INPUT
SOURCES
DESCRIPTION
The ST1534A is intended for application such as
power managed PCI and network interface cards
(NICs), where operations from 3.3V VAUX supply
SCHEMATIC DIAGRAM
VIN
P²PAK
PPAK
SO-8
may be required when the 5V supply has been
shut down.
During regular operation, 3.3V power for the PCI
card is provided by the internal LDO regulator,
generated from 5V supply. When the 5V V_AUX is
available, the IC connects this supply directly to its
output using an external P-Channel FET. This
ensures an uninterrupted 3.3V out even if VIN falls
out of specification.
When both supplies are available simultaneously,
the drive pin DR will be pulled high, turning off the
PMOS switch.
The device is available in the popular 5 leads
P²PAK and PPAK
April 2003
+
5V Detect
-
VIN
Reference
+
Error
-^Amp
GND
DR
Rpull_down
VOUT
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