LP3963/LP3966
3A Fast Ultra Low Dropout Linear Regulators
General Description
The LP3963/LP3966 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 fast to step
changes in load which makes them suitable for low voltage
microprocessor applications. The LP3963/LP3966 are de-
veloped on a CMOS process which allows low quiescent
current operation independent of output load current.This
CMOS process also allows the LP3963/LP3966 to operate
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 15A quiescent current when
the shutdown pin is pulled low.
Error Flag: Error flag goes low when the output voltage
drops 10% below nominal value (for LP3963).
SENSE: Sense pin improves regulation at remote loads.
(For LP3966)
Precision Output Voltage: Multiple output voltage options
are available ranging from 1.2V to 5.0V and adjustable, with
a guaranteed accuracy of
1.5% at room temperature, and
3.0% over all conditions ( varying line, load, and tempera-
ture).
Features
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Ultra low dropout voltage
n
Low ground pin current
n
Load regulation of 0.06%
n
15A quiescent current in shutdown mode
n
Guaranteed output current of 3A DC
n
Available in TO-263 and TO-220 packages
n
Output voltage accuracy
1.5%
n
Error flag indicates output status (LP3963)
n
Sense option improves better load regulation (LP3966)
n
Extremely low 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
DS101267-1
# Minimum output capacitance is 10 F to ensure stability over full load current range. More capacitance provides superior dynamic performance and additional
stability margin.
*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 applications sec-
tion for more information.
April 2000
LP3963/LP3966
3A
Fast
Ultra
Low
Dropout
Linear
Regulators
2000 National Semiconductor Corporation
DS101267
www.national.com
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