LP3883 3A Fast-Response Ultra Low Dropout Linear Regulators
August 2003
LP3883
3A Fast-Response Ultra Low Dropout Linear Regulators
General Description
The LP3883 is a high-current, fast-response regulator which
can maintain output voltage regulation with minimum input to
output voltage drop. Fabricated on a CMOS process, the
device operates from two input voltages: Vbias provides
voltage to drive the gate of the N-MOS power transistor,
while Vin is the input voltage which supplies power to the
load. The use of an external bias rail allows the part to
operate from ultra low Vin voltages. Unlike bipolar regula-
tors, the CMOS architecture consumes extremely low quies-
cent current at any output load current. The use of an
N-MOS power transistor results in wide bandwidth, yet mini-
mum external capacitance is required to maintain loop sta-
bility.
The fast transient response of these devices makes them
suitable for use in powering DSP, Microcontroller Core volt-
ages and Switch Mode Power Supply post regulators. The
parts are available in TO-220 and TO-263 packages.
Dropout Voltage:
210 mV (typ)
@
3A load current.
Ground Pin Current:
3 mA (typ) at full load.
Shutdown Current:
60 nA (typ) when S/D pin is low.
Precision Output Voltage:
1.5% room temperature accu-
racy.
Features
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Ultra low dropout voltage (210 mV
@
3A typ)
Low ground pin current
Load regulation of 0.04%/A
60 nA typical quiescent current in shutdown
1.5% output accuracy (25藲C)
TO-220, TO-263 packages
Over temperature/over current protection
鈭?0藲C to +125藲C junction temperature range
Applications
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DSP Power Supplies
Server Core and I/O Supplies
Linear Power Supplies for PC Add-in-Cards
Set-Top Box Power Supplies
Microprocessor Power Supplies
High Efficiency Linear Power Supplies
SMPS Post-Regulators
Typical Application Circuit
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At least 4.7 碌F of input and output capacitance is required for stability.
Connection Diagrams
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TO-220, Top View
TO-263, Top View
漏 2003 National Semiconductor Corporation
DS200624
www.national.com