LP38859

3A Fast-Response High-Accuracy LDO Linear Regulator

with Soft-Start

General Description

The LP38859 is a high current, fast response regulator

which can maintain output voltage regulation with extremely

low input to output voltage drop. Fabricated on a CMOS

process, the device operates from two input voltages: V

BIAS

provides voltage to drive the gate of the N-MOS power

transistor, while V

IN

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 V

regulators, the CMOS architecture consumes extremely low

quiescent 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 this device makes it suitable

for use in powering DSP, Microcontroller Core voltages and

Switch Mode Power Supply post regulators. The LP38859 is

available in TO-220 and TO-263 5-Lead packages.

Dropout Voltage: 240 mV (typical) at 3A load current.

Low Ground Pin Current: 14 mA (typical) at 3A load cur-

rent.

Soft-Start: Programmable Soft-Start time.

for 0˚C

≤ T

J

≤ +125˚C, across all line and load conditions

Features

n

Standard V

n

Stable with 10µF Ceramic capacitors

n

Dropout voltage of 240 mV (typical) at 3A load current

n

Precision Output Voltage across all line and load

conditions:

≤ T

J

≤ +125˚C

≤ T

J

≤ +125˚C

n

Over-Temperature and Over-Current protection

n

Available in 5 lead TO-220 and TO-263 packages

n

Custom V

available

n

−40˚C to +125˚C Operating Temperature Range

Applications

n

ASIC Power Supplies In:

- Desktops, Notebooks, and Graphics Cards, Servers

- Gaming Set Top Boxes, Printers and Copiers

n

Server Core and I/O Supplies

n

DSP and FPGA Power Supplies

n

SMPS Post-Regulator

Typical Application Circuit

20131201

June 2006

© 2006 National Semiconductor Corporation

DS201312

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