LP3961/LP3964
800mA Fast Ultra Low Dropout Linear Regulators
LP3961/LP3964 800mA Fast Ultra Low Dropout Linear Regulators
May 2000
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 developed 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, with
a guaranteed accuracy of
±
3.0% over all conditions ( varying line, load, and tempera-
ture).
±
1.5% at room temperature, and
Features
n Ultra low dropout voltage
n Low ground pin current
n Load regulation of 0.02%
n 15µA 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
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 −40˚C to +125˚C junction temperature range
±
1.5%
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 µF 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 10kΩ pull-up resistor. Connect the ERROR pin to ground if this function is not used. See applications section for more information.
Minimum output capacitance is 10 µF 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 10kΩ pull-up resistor. Connect the ERROR pin to ground if this function is not used. See applications section
for more information.
DS101129-2
Block Diagram LP3961
DS101129-3
www.national.com2
Block Diagram LP3964
Block Diagram LP3964-ADJ
LP3961/LP3964
DS101129-29
Connection Diagrams
DS101129-30
DS101129-4
Top View
SOT 223-5 Package
www.national.com3
Connection Diagrams (Continued)
LP3961/LP3964
DS101129-5
Top View
TO220-5 Package
Bent, Staggered Leads
DS101129-6
Top View
TO263-5 Package
Pin Description for SOT223-5 Package
#
Pin
NameFunctionNameFunction
1SD
2V
3V
IN
OUT
4ERROR
5GNDGroundGNDGround
LP3961LP3964
ShutdownSDShutdown
Input SupplyV
Output VoltageV
IN
OUT
ERROR FlagSENSE/ADJRemote Sense Pin
Pin Description for TO220-5 and TO263-5 Packages
#
Pin
NameFunctionNameFunction
1SD
2V
IN
3GNDGroundGNDGround
4V
OUT
5ERROR
LP3961LP3964
ShutdownSDShutdown
Input SupplyV
Output VoltageV
IN
OUT
ERROR FlagSENSE/ADJRemote Sense Pin
Input Supply
Output Voltage
or output Adjust Pin
Input Supply
Output Voltage
or output Adjust Pin
www.national.com4
Ordering Information
Package Type Designator is ″MP″ for SOT223 package, ″T″ for TO220 package, and ″S″ for TO263 package.
TABLE 1. Package Marking and Ordering Information
LP3961/LP3964
DS101129-31
Output
Voltage
5.0LP3961EMP-5.0800mA, Error Flag
5.0LP3961EMPX-5.0800mA, Error Flag
3.3LP3961EMP-3.3800mA, Error Flag
3.3LP3961EMPX-3.3800mA, Error Flag
2.5LP3961EMP-2.5800mA, Error Flag
2.5LP3961EMPX-2.5800mA, Error Flag
1.8LP3961EMP-1.8800mA, Error Flag
1.8LP3961EMPX-1.8800mA, Error Flag
5.0LP3964EMP-5.0800mA, SENSESOT223-5LBUB1000 units on
5.0LP3964EMPX-5.0800mA, SENSESOT223-5LBUB2000 units on
3.3LP3964EMP-3.3800mA, SENSESOT223-5LBJB1000 units on
3.3LP3964EMPX-3.3800mA, SENSESOT223-5LBJB2000 units on
2.5LP3964EMP-2.5800mA, SENSESOT223-5LBHB1000 units on
2.5LP3964EMPX-2.5800mA, SENSESOT223-5LBHB2000 units on
1.8LP3964EMP-1.8800mA, SENSESOT223-5LBFB1000 units on
1.8LP3964EMPX-1.8800mA, SENSESOT223-5LBFB2000 units on
ADJLP3964EMP-ADJ800mA, ADJSOT223-5LBPB1000 units on
Order NumberDescription
(Current, Option)
Package
Type
SOT223-5LBSB1000 units on
SOT223-5LBSB2000 units on
SOT223-5LAZB1000 units on
SOT223-5LAZB2000 units on
SOT223-5LBBB1000 units on
SOT223-5LBBB2000 units on
SOT223-5LBAB1000 units on
SOT223-5LBAB2000 units on
Package MarkingSupplied As:
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
www.national.com5
Ordering Information (Continued)
TABLE 1. Package Marking and Ordering Information (Continued)
Output
Voltage
LP3961/LP3964
ADJLP3964EMPX-ADJ800mA, ADJSOT223-5LBPB2000 units on
1.8LP3964ESX-1.8800mA, SENSETO263-5LP3964ES-1.8Tape and Reel
ADJLP3964ES-ADJ800mA, ADJTO263-5LP3964ES-ADJRail
ADJLP3964ESX-ADJ800mA, ADJTO263-5LP3964ES-ADJTape and Reel
TO263-5LP3961ES-5.0Rail
TO263-5LP3961ESX-5.0Tape and Reel
TO263-5LP3961ES-3.3Rail
TO263-5LP3961ES-3.3Tape and Reel
TO263-5LP3961ES-2.5Rail
TO263-5LP3961ES-2.5Tape and Reel
TO263-5LP3961ES-1.8Rail
TO263-5LP3961ES-1.8Tape and Reel