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 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 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, with
a guaranteed accuracy of
1.5% at room temperature, and
3.0% over all conditions ( varying line, load, and tempera-
ture).
Features
n
Ultra low dropout voltage
n
Low ground pin current
n
Load regulation of 0.02%
n
15A quiescent current in shutdown mode
n
Guaranteed output current of 0.8A DC
n
Available in SOT-223,TO-263 and TO-220 packages
n
Output voltage accuracy
1.5%
n
Error flag indicates output status (LP3961)
n
Sense option improves better load regulation (LP3964)
n
Extremely low output capacitor requirements
n
Overtemperature/overcurrent protection
n
-40C to +125C junction temperature range
Applications
n
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
DS101129-1
# 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.
May 2000
LP3961/LP3964
800mA
Fast
Ultra
Low
Dropout
Linear
Regulators
2000 National Semiconductor Corporation
DS101129
www.national.com
Ordering Information
TABLE 1. Package Marking and Ordering Information
Output
Voltage
Order Number
Description
(Current, Option)
Package
Type
Package Marking
Supplied As:
5.0
LP3961EMP-5.0
800mA, Error Flag
SOT223-5
LBSB
1000 units on
Tape and Reel
5.0
LP3961EMPX-5.0
800mA, Error Flag
SOT223-5
LBSB
2000 units on
Tape and Reel
3.3
LP3961EMP-3.3
800mA, Error Flag
SOT223-5
LAZB
1000 units on
Tape and Reel
3.3
LP3961EMPX-3.3
800mA, Error Flag
SOT223-5
LAZB
2000 units on
Tape and Reel
2.5
LP3961EMP-2.5
800mA, Error Flag
SOT223-5
LBBB
1000 units on
Tape and Reel
2.5
LP3961EMPX-2.5
800mA, Error Flag
SOT223-5
LBBB
2000 units on
Tape and Reel
1.8
LP3961EMP-1.8
800mA, Error Flag
SOT223-5
LBAB
1000 units on
Tape and Reel
1.8
LP3961EMPX-1.8
800mA, Error Flag
SOT223-5
LBAB
2000 units on
Tape and Reel
5.0
LP3964EMP-5.0
800mA, SENSE
SOT223-5
LBUB
1000 units on
Tape and Reel
5.0
LP3964EMPX-5.0
800mA, SENSE
SOT223-5
LBUB
2000 units on
Tape and Reel
3.3
LP3964EMP-3.3
800mA, SENSE
SOT223-5
LBJB
1000 units on
Tape and Reel
3.3
LP3964EMPX-3.3
800mA, SENSE
SOT223-5
LBJB
2000 units on
Tape and Reel
2.5
LP3964EMP-2.5
800mA, SENSE
SOT223-5
LBHB
1000 units on
Tape and Reel
2.5
LP3964EMPX-2.5
800mA, SENSE
SOT223-5
LBHB
2000 units on
Tape and Reel
1.8
LP3964EMP-1.8
800mA, SENSE
SOT223-5
LBFB
1000 units on
Tape and Reel
1.8
LP3964EMPX-1.8
800mA, SENSE
SOT223-5
LBFB
2000 units on
Tape and Reel
ADJ
LP3964EMP-ADJ
800mA, ADJ
SOT223-5
LBPB
1000 units on
Tape and Reel
DS101129-31
Package Type Designator is
MP
for SOT223 package,
T
for TO220 package, and
S
for TO263 package.
LP3961/LP3964
www.national.com
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