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LP3961/LP3964 800mA Fast Ultra Low Dropout Linear Regulators
September 2006
LP3961/LP3964
800mA Fast Ultra Low Dropout Linear Regulators
General Description
The LP3961/LP3964 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 LP3961/LP3964 are de-
veloped on a CMOS process which allows low quiescent
current operation independent of output load current. This
CMOS process also allows the LP3961/LP3964 to operate
under extremely low dropout conditions.
Dropout Voltage:
Ultra low dropout voltage; typically 24mV
at 80mA load current and 240mV at 800mA load current.
Ground Pin Current:
Typically 4mA at 800mA load current.
Shutdown Mode:
Typically 15µA 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 LP3961).
SENSE:
Sense pin improves regulation at remote loads.
(For LP3964)
Precision Output Voltage:
Multiple output voltage options
are available ranging from 1.2V to 5.0V and adjustable
(LP3964), 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 0.02%
15µA quiescent current in shutdown mode
Guaranteed output current of 0.8A DC
Available in SOT-223,TO-263 and TO-220 packages
Output voltage accuracy
±
1.5%
Error flag indicates output status (LP3961)
Sense option improves better load regulation (LP3964)
Extremely low output capacitor requirements
Overtemperature/overcurrent protection
−40˚C to +125˚C junction temperature range
Applications
n
n
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n
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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
10112901
*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 applications
section for more information.
** See Application Hints.
© 2006 National Semiconductor Corporation
DS101129
www.national.com
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