May 2003
LP3963/LP3966
3A Fast Ultra Low Dropout Linear Regulators
General Description
Features
n Ultra low dropout voltage
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 quickly to
step changes in load which makes them suitable for low
voltage microprocessor applications. The LP3963/LP3966
are developed on a CMOS process which allows low quies-
cent current operation independent of output load current.
This CMOS process also allows the LP3963/LP3966 to op-
erate under extremely low dropout conditions.
n Low ground pin current
n Load regulation of 0.06%
n 15µA 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 load regulation (LP3966)
n Minimum output capacitor requirements
n Overtemperature/overcurrent protection
n −40˚C to +125˚C junction temperature range
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 15µA quiescent current when
the shutdown pin is pulled low.
Applications
n Microprocessor power supplies
n GTL, GTL+, BTL, and SSTL bus terminators
n Power supplies for DSPs
n SCSI terminator
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)
n Post regulators
n High efficiency linear regulators
n Battery chargers
Precision Output Voltage: Multiple output voltage options
are available ranging from 1.2V to 5.0V and adjustable
(LP3966), with a guaranteed accuracy of 1.5% at room
temperature, and 3.0% over all conditions (varying line,
load, and temperature).
n Other battery powered applications
Typical Application Circuits
10126701
*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
© 2003 National Semiconductor Corporation
DS101267
www.national.com