LP38859-1.2EVAL National Semiconductor, LP38859-1.2EVAL Datasheet

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LP38859-1.2EVAL

Manufacturer Part Number
LP38859-1.2EVAL
Description
BOARD EVALUATION LP38859-1.2
Manufacturer
National Semiconductor
Series
PowerWise®r
Datasheets

Specifications of LP38859-1.2EVAL

Channels Per Ic
1 - Single
Voltage - Output
1.2V
Current - Output
3A
Voltage - Input
3 ~ 5.5V
Regulator Type
Positive Fixed
Operating Temperature
-40°C ~ 125°C
Board Type
Fully Populated
Utilized Ic / Part
LP38859
Lead Free Status / RoHS Status
Not applicable / Not applicable
© 2007 National Semiconductor Corporation
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 in-
put to output voltage drop. Fabricated on a CMOS process,
the device operates from two input voltages: V
voltage to drive the gate of the N-MOS power transistor, while
V
use of an external bias rail allows the part to operate from ultra
low V
tecture consumes extremely low quiescent current at any
output load current. The use of an N-MOS power transistor
results in wide bandwidth, yet minimum external capacitance
is required to maintain loop stability.
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 current.
Soft-Start: Programmable Soft-Start time.
Precision Output Voltage: ±1.0% for T
for 0°C
Typical Application Circuit
IN
is the input voltage which supplies power to the load. The
IN
voltages. Unlike bipolar regulators, the CMOS archi-
T
J
+125°C, across all line and load conditions
J
201312
= 25°C and ±2.0%
BIAS
provides
Features
Applications
Standard V
Wide V
Stable with 10µF Ceramic capacitors
Dropout voltage of 240 mV (typical) at 3A load current
Precision Output Voltage across all line and load
conditions:
— ±1.0% V
— ±2.0% V
— ±3.0% V
Over-Temperature and Over-Current protection
Available in 5 lead TO-220 and TO-263 packages
Custom V
−40°C to +125°C Operating Temperature Range
ASIC Power Supplies In:
- Desktops, Notebooks, and Graphics Cards, Servers
- Gaming Set Top Boxes, Printers and Copiers
Server Core and I/O Supplies
DSP and FPGA Power Supplies
SMPS Post-Regulator
BIAS
OUT
OUT
Supply operating range of 3.0V to 5.5V
OUT
OUT
OUT
values between 0.8V and 1.2V are available
values of 0.8V and 1.2V
for T
for 0°C
for -40°C
J
= 25°C
T
J
T
J
20131201
+125°C
+125°C
November 2006
www.national.com

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LP38859-1.2EVAL Summary of contents

Page 1

... 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 in- put to output voltage drop. Fabricated on a CMOS process, the device operates from two input voltages: V ...

Page 2

... Ordering Information V * Order Number OUT LP38859S-0.8 0.8V LP38859SX-0.8 LP38859T-0.8 LP38859S-1.2 1.2V LP38859SX-1.2 LP38859T-1.2 * For custom V values between 0.8V and 1.2V please contact the National Semiconductor Sales Office. OUT Connection Diagrams TO263–5, Top View Pin Descriptions Pin # Pin Symbol GND 4 OUT ...

Page 3

... V rising until device is BIAS functional V falling from UVLO threshold BIAS until device is non-functional 1V, IN OUT(NOM 3.0V 0.0V BIAS OUT LP38859-0.8 LP38859-1.2 LP38859-0. LP38859-1. −0.3V to +6.0V −0.3V to +6.0V Internally Limited −40°C to +150°C (Note OUT DO BIAS 3. 3.0A −40°C to +125° ...

Page 4

Symbol Parameter AC Parameters PSRR Ripple Rejection for Voltage IN PSRR Ripple Rejection for V BIAS (V ) BIAS Output Noise Density e Output Noise Voltage 1.8V OUT Thermal Parameters Thermal Shutdown Junction ...

Page 5

Typical Performance Characteristics V = 3.0V mA BIAS OUT IN OUT V Ground Pin Current (I BIAS GND(BIAS) V Ground Pin Current vs Temperature IN Dropout Voltage ( Temperature DO Unless otherwise ...

Page 6

V vs Temperature OUT Soft-Start Resistor ( Temperature OUT SS www.national.com UVLO Thresholds vs Temperature 20131267 Soft-Start r SS 20131274 V Line Transient Response IN 20131276 6 20131268 ...

Page 7

V Line Transient Response IN V Line Transient Response BIAS Load Transient Response µF Ceramic OUT V Line Transient Response BIAS 20131278 Load Transient Response, C 20131280 Load Transient Response, C 20131282 7 20131279 = 10 µF ...

Page 8

Load Transient Response, C Load Transient Response PSRR IN www.national.com = 100 µF Ceramic Load Transient Response, C OUT 20131284 = 100 µF Tantalum OUT 20131286 20131271 8 = 100 µF Tantalum OUT 20131285 V PSRR BIAS 20131270 ...

Page 9

Block Diagram 9 20131205 www.national.com ...

Page 10

... R output to input voltage differential. This condition is outside the guaranteed operating range and should be avoided. SOFT-START The LP38859 incorporates a Soft-Start function that reduces the start-up current surge into the output capacitor (C allowing V to rise slowly to the final value. This is accom- ...

Page 11

C discharge circuit will cease to function due lack of sufficient biasing to the control circuitry. Since V appears on the SS pin, any leakage through C REF will cause V to fall, and thus ...

Page 12

Heat-Sinking The TO-263 Package The TO-263 package has a θ rating of 60°C/W, and a θ JA rating of 3°C/W. These ratings are for the package only, no additional heat-sinking, and with no airflow. The TO-263 package uses the copper ...

Page 13

Physical Dimensions inches (millimeters) unless otherwise noted TO-220 5-Lead, Stagger Bend Package (TO220-5) TO-263 5-Lead, Molded, Surface Mount Package (TO263-5) NS Package Number TO5D NS Package Number TS5B 13 www.national.com ...

Page 14

... National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other brand or product names may be trademarks or registered trademarks of their respective holders. ...

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