LP3872/LP3875
1.5A Fast Ultra Low Dropout Linear Regulators
General Description
The LP3872/LP3875 series of fast ultra low-dropout linear
regulators operate from a +2.5V to +7.0V input supply. Wide
range of preset output voltage options are available. These
ultra low dropout linear regulators respond very quickly to
step changes in load, which makes them suitable for low
voltage microprocessor applications. The LP3872/LP3875
are developed on a CMOS process which allows low quies-
cent current operation independent of output load current.
This CMOS process also allows the LP3872/LP3875 to op-
erate under extremely low dropout conditions.
Dropout Voltage: Ultra low dropout voltage; typically 38mV
at 150mA load current and 380mV at 1.5A load current.
Ground Pin Current: Typically 6mA at 1.5A load current.
Shutdown Mode: Typically 10nA quiescent current when
the shutdown pin is pulled low.
Error Flag: Error flag goes low when the output voltage
drops 10% below nominal value.
SENSE: Sense pin improves regulation at remote loads.
Precision Output Voltage: Multiple output voltage options
are available ranging from 1.8V to 5.0V with a guaranteed
accuracy of
1.5% at room temperature, and
3.0% over all
conditions (varying line, load, and temperature).
Features
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Ultra low dropout voltage
n
Low ground pin current
n
Load regulation of 0.06%
n
10nA quiescent current in shutdown mode
n
Guaranteed output current of 1.5A DC
n
Available in TO-263, TO-220 and SOT-223 packages
n
Output voltage accuracy
1.5%
n
Error flag indicates output status
n
Sense option improves load regulation
n
Minimum output capacitor requirements
n
Overtemperature/overcurrent protection
n
-40C to +125C junction temperature range
Applications
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Microprocessor power supplies
n
GTL, GTL+, BTL, and SSTL bus terminators
n
Power supplies for DSPs
n
SCSI terminator
n
Post regulators
n
High efficiency linear regulators
n
Battery chargers
n
Other battery powered applications
Typical Application Circuits
20063301
*SD and ERROR pins must be pulled high through a 10k
pull-up resistor. Connect the ERROR pin to ground if this function is not used. See application hints
for more information.
July 2005
LP3872/LP3875
1.5A
Fast
Ultra
Low
Dropout
Linear
Regulators
2005 National Semiconductor Corporation
DS200633
www.national.com
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