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LP3873/LP3876 3A Fast Ultra Low Dropout Linear Regulators
September 2006
LP3873/LP3876
3A Fast Ultra Low Dropout Linear Regulators
General Description
The LP3873/LP3876 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 LP3873/LP3876
are developed on a CMOS process which allows low quies-
cent current operation independent of output load current.
This CMOS process also allows the LP3873/LP3876 to op-
erate under extremely low dropout conditions.
Dropout Voltage:
Ultra low dropout voltage; typically 80mV
at 300mA load current and 800mV at 3A load current.
Ground Pin Current:
Typically 6mA at 3A load current.
Shutdown Mode:
Typically 1µA 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
n
n
n
n
n
n
n
n
n
n
n
n
Ultra low dropout voltage
Low ground pin current
Load regulation of 0.08%
1µA quiescent current in shutdown mode
Guaranteed output current of 3A DC
Available in TO-263 and TO-220 packages
Output voltage accuracy
±
1.5%
Error flag indicates output status
Sense option improves load regulation
Minimum output capacitor requirements
Overtemperature/overcurrent protection
−40˚C to +125˚C junction temperature range
Applications
n
n
n
n
n
n
n
n
Microprocessor power supplies
GTL, GTL+, BTL, and SSTL bus terminators
Power supplies for DSPs
SCSI terminator
Post regulators
High efficiency linear regulators
Battery chargers
Other battery powered applications
Typical Application Circuits
20060501
*SD and ERROR pins must be pulled high through a 10kΩ pull-up resistor. Connect the ERROR pin to ground if this function is not used. See application hints
for more information.
© 2006 National Semiconductor Corporation
DS200605
www.national.com
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