LP38851 - 800 mA Fast-Response High-Accuracy Adjustable LDO Linear Regulator with Enable and Soft-Start

LP38851 - 800 mA Fast-Response High-Accuracy Adjustable LDO Linear Regulator with Enable and Soft-Start from the PowerWise® Family

Datasheet	Packaging	Samples & Pricing	Reliability	Design Tools	Application Notes	Knowledge Base

Features

•	Adjustable V_OUT range of 0.80V to 1.8V
•	Wide V_BIAS Supply operating range of 3.0V to 5.5V
•	Stable with 10µF Ceramic capacitors
•	Dropout voltage of 115 mV (typical) at 800 mA load current
•	Precision V_ADJ across all line and load conditions:
•	±1.5% V_ADJ for T_J = 25°C
•	±2.0% V_ADJ for 0°C ≤ T_J ≤ +125°C
•	±3.0% V_ADJ for -40°C ≤ T_J ≤ +125°C
•	Over-Temperature and Over-Current protection
•	Available in 8 lead PSOP, 7 lead TO-220 and 7 lead TO-263 packages
•	−40°C to +125°C Operating Junction Temperature Range

General Description

The LP38851-ADJ is a high current, fast response regulator which can maintain output voltage regulation with extremely low input to output voltage drop. More...

Applications

•	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

Typical Application

*click for larger image

LP38851-ADJ Typical Application Circuit

Parameters Values

Output Current 800 mA

Output Min 0.80 Volt

Input Max Voltage 5.5 Volt

Dropout Voltage 0.115 Volt

Adjustable Output Yes

Quiescent Current 10 mA

On/Off Pin Yes

Error Flag No

RegType LDO

Temperature Min -40 deg C

Temperature Max 125 deg C

Special Features Dual Rail, Soft-Start

Output Max 1.80 Volt

PowerWise Yes

Typical Performance

*click for larger image

Ultra-Low Dropout Performance

Also Recommended

LP38852▲	1.5A Version
LP38853▲	3A Version

Additional Resources

Design Tools

Application Notes

Block Diagram

*click for larger image

LP38851-ADJ Block Diagram

Datasheet

RoHS Compliance Information	Size in Kbytes	Date
LP38851 800 mA Fast-Response High-Accuracy Adjustable LDO Linear Regulator with Enable and Soft-Start	443 Kbytes	26-Jun-07	Download
LP38851 800 mA Fast-Response High-Accuracy Adjustable LDO Linear Regulator with Enable and Soft-Start (Japanese)	737 Kbytes

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Package Availability, Models, Samples & Pricing

Part Number

Package

Factory Lead Time

Models

Samples &
Electronic
Orders

Budgetary Pricing

Std
Pack
Size

Package
Marking
Format

Type

Pins

Spec.

MSL
Rating

Peak
Reflow

RoHS
Report

CAD
Symbols

Weeks

Qty

$US each

LP38851MR-ADJ

PSOP

NOPB

260

RoHS

Download

Full production

N/A

1K+

$1.20

rail
of
95

NSXYTT
L38851
MRADJ

6 weeks

N/A

LP38851MRX-ADJ

PSOP

NOPB

260

RoHS

Download

Full production

N/A

1K+

$1.20

reel
of
2500

NSXYTT
L38851
MRADJ

6 weeks

N/A

LP38851T-ADJ

TO-220

NOPB

RoHS

Download

Full production

N/A

1K+

$1.20

rail
of
45

NSUZXYTTE#
LP38851T
-ADJ

6 weeks

N/A

LP38851S-ADJ

TO-263

NOPB

245

RoHS

Download

Full production

N/A

1K+

$1.20

rail
of
45

NSUZXYTTE#
LP38851S
-ADJ

6 weeks

N/A

LP38851SX-ADJ

TO-263

NOPB

245

RoHS

Download

Full production

N/A

1K+

$1.20

reel
of
500

NSUZXYTTE#
LP38851S
-ADJ

6 weeks

N/A

General Description

The LP38851-ADJ 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_IN voltages. Unlike bipolar 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 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 part is available in PSOP 8–pin, TO-220 7–pin, and TO-263 7-pin packages.

Dropout Voltage: 115 mV (typical) at 800 mA load current.

Low Ground Pin Current: 10 mA (typical) at 800 mA load current.

Soft-Start: Programmable Soft-Start time.

Precision ADJ Voltage: ±1.5% for T_J = 25°C, and ±2.0% for 0°C ≤ T_J ≤ +125°C, across all line and load conditions

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Device Hours	FITS	MTTF (Hours)
LP38851MR-ADJ	CS065	2	38968	52	4402000	1	1249079519
LP38851MRX-ADJ	CS065	2	38968	52	4402000	1	1249079519
LP38851S-ADJ	CS065	2	38968	52	4402000	1	1249079519
LP38851SX-ADJ	CS065	2	38968	52	4402000	1	1249079519
LP38851T-ADJ	CS065	2	38968	52	4402000	1	1249079519

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

For more information on Reliability Metrics, please click here.

Design Tools

Title	Size in Kbytes	Date
Article - How to Power Sub-Micron CMOS Loads with an Efficient LDO			View

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More Application Notes

Title	Size in Kbytes	Date
AN-1560: Application Note 1560 LP38852MR-ADJ Evaluation Board	280 Kbytes	17-Mar-07	Download
AN-1560 (Chinese): Application Note 1560 LP38852MR-ADJ Evaluation Board	397 Kbytes
AN-1479: Application Note 1479 LP38856S-1.2 Evaluation Board	468 Kbytes	3-Nov-06	Download
AN-1479 (Chinese): Application Note 1479 LP38856S-1.2 Evaluation Board	230 Kbytes
AN-1504: Application Note 1504 LP38853S-ADJ Evaluation Board	573 Kbytes	13-Mar-07	Download
AN-1504 (Chinese): Application Note 1504 LP38853S-ADJ Evaluation Board	285 Kbytes
AN-1480: Application Note 1480 LP38859S-1.2 Evaluation Board	522 Kbytes	3-Nov-06	Download
AN-1480 (Chinese): Application Note 1480 LP38859S-1.2 Evaluation Board	228 Kbytes
AN-1815: Application Note 1815 LDOs Ease the Stress of Start-Up	149 Kbytes	23-Sep-08	Download

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[Information as of 8-Nov-2009]