LP3891 - 0.8A Fast-Response Ultra Low Dropout Linear Regulators

LP3891 - 0.8A Fast-Response Ultra Low Dropout Linear Regulators

Datasheet	Packaging	Samples & Pricing	Reliability	Application Notes	Knowledge Base

Features

•	Ultra low dropout voltage (100mV @ 0.8A typ)
•	Low ground pin current
•	Load regulation of 0.04%/A
•	60 nA typical quiescent current in shutdown
•	1.5% output accuracy (25°C)
•	TO-220, TO-263 and PSOP-8 packages
•	Over temperature/over current protection
•	-40°C to +125°C junction temperature range

General Description

The LP3891 is a high current, fast response regulator which can maintain output voltage regulation with minimum input to output voltage drop. More...

Applications

•	DSP Power Supplies
•	Server Core and I/O Supplies
•	PC Add-in-Cards
•	Local Regulators in Set-Top Boxes
•	Microcontroller Power Supplies
•	High Efficiency Power Supplies
•	SMPS Post-Regulators

Typical Application

click for larger image

Parameters Values

Output Current 800 mA

Output Min 1.8, 1.2, 1.5 Volt

Input Min Voltage 1.9, 1.3, 1.6 Volt

Input Max Voltage 5.5 Volt

Dropout Voltage 0.1 Volt

Adjustable Output No

Quiescent Current 4 mA

On/Off Pin Yes

Error Flag No

RegType LDO

Temperature Min -40 deg C

Temperature Max 125 deg C

Output Voltage 1.8, 1.2, 1.5 Volt

Output Max 1.8, 1.2, 1.5 Volt

Typical Performance

*click for larger image

Also Recommended

LP3881▲	Has Less Than Half The Dropout Voltage
LP38841▲	Vout Down To 0.56V, Vin Down To 1.05V
LP3892▲	1.5A Version

Additional Resources

Application Notes

Block Diagram

click for larger image

Datasheet

RoHS Compliance Information	Size in Kbytes	Date
LP3891 0.8A Fast-Response Ultra Low Dropout Linear Regulators	737 Kbytes	21-Jun-06	Download

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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

Qty

Qty

$US each

LP3891EMR-1.5

8

NOPB

3

260

Lifetime buy

N/A

Buy Now

1K+

$1.27

rail
of
95

NSXYTT
3891E
MR1.5

8 weeks

500

LP3891EMR-1.2

8

NOPB
STD

3
3

260
260

Full production

N/A

Samples

Buy Now

1K+

$1.27

rail
of
95

NSXYTT
3891E
MR1.2

8 weeks

500

LP3891EMR-1.8

8

NOPB
STD

3
3

260
260

Full production

N/A

Buy Now

1K+

$1.27

rail
of
95

NSXYTT
3891E
MR1.8

8 weeks

500

LP3891EMRX-1.5

8

NOPB

3

260

Lifetime buy

N/A

Buy Now

1K+

$1.27

reel
of
2500

NSXYTT
3891E
MR1.5

8 weeks

5000

LP3891EMRX-1.8

8

Lifetime buy

N/A

Buy Now

1K+

$1.27

reel
of
2500

NSXYTT
3891E
MR1.8

16 weeks

N/A

LP3891EMRX-1.2

8

NOPB

3

260

Full production

N/A

Buy Now

1K+

$1.27

reel
of
2500

NSXYTT
3891E
MR1.2

8 weeks

3000

LP3891ET-1.2

5

NOPB

1

NA

Lifetime buy

N/A

Buy Now

1K+

$1.27

rail
of
45

NSUZXYTTE#
LP3891ET
-1.2

8 weeks

N/A

LP3891ET-1.5

5

NOPB

1

NA

Lifetime buy

N/A

Buy Now

1K+

$1.27

rail
of
45

NSUZXYTTE#
LP3891ET
-1.5

8 weeks

N/A

LP3891ET-1.8

5

NOPB

1

NA

Lifetime buy

N/A

Buy Now

1K+

$1.27

rail
of
45

NSUZXYTTE#
LP3891ET
-1.8

8 weeks

N/A

LP3891ES-1.8

5

NOPB
STD

3
3

245
235

Lifetime buy

N/A

Buy Now

1K+

$1.27

rail
of
45

NSUZXYTTE#
LP3891ES
-1.8

8 weeks

500

LP3891ES-1.2

5

NOPB

3

245

Full production

N/A

Samples

Buy Now

1K+

$1.27

rail
of
45

NSUZXYTTE#
LP3891ES
-1.2

8 weeks

1000

LP3891ES-1.5

5

NOPB

3

245

Full production

N/A

Buy Now

1K+

$1.27

rail
of
45

NSUZXYTTE#
LP3891ES
-1.5

8 weeks

500

LP3891ESX-1.8

5

NOPB

3

245

Lifetime buy

N/A

Buy Now

1K+

$1.27

reel
of
500

NSUZXYTTE#
LP3891ES
-1.8

8 weeks

2000

LP3891ESX-1.2

5

NOPB

3

245

Full production

N/A

Buy Now

1K+

$1.27

reel
of
500

NSUZXYTTE#
LP3891ES
-1.2

8 weeks

2000

LP3891ESX-1.5

5

NOPB

3

245

Full production

N/A

Buy Now

1K+

$1.27

reel
of
500

NSUZXYTTE#
LP3891ES
-1.5

8 weeks

2000

Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LP3891EMR-1.5	NONE	NATIONAL SEMICONDUCTOR	01 Dec 2009
LP3891EMRX-1.5	NONE	NATIONAL SEMICONDUCTOR	01 Dec 2009
LP3891EMRX-1.8	NONE	NATIONAL SEMICONDUCTOR	01 Dec 2009
LP3891ES-1.8	NONE	NATIONAL SEMICONDUCTOR	01 Dec 2009
LP3891ESX-1.8	NONE	NATIONAL SEMICONDUCTOR	01 Dec 2009
LP3891ET-1.2	NONE	NATIONAL SEMICONDUCTOR	01 Dec 2009
LP3891ET-1.5	NONE	NATIONAL SEMICONDUCTOR	01 Dec 2009
LP3891ET-1.8	NONE	NATIONAL SEMICONDUCTOR	01 Dec 2009

General Description

The LP3891 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 regulators, the CMOS architectutre 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 these devices makes them suitable for use in powering DSP, Microcontroller Core voltages and Switch Mode Power Supply post regulators. The parts are available in TO-220, TO-263 and PSOP-8 packages.

Dropout Voltage: 100 mV (typ) @ 0.8A 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 accuracy.

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LP3891EMR-1.2	CS065	2	38968	52	0	4402000	1	1249079519
LP3891EMR-1.5	CS065	2	38968	52	0	4402000	1	1249079519
LP3891EMR-1.8	CS065	2	38968	52	0	4402000	1	1249079519
LP3891EMRX-1.2	CS065	2	38968	52	0	4402000	1	1249079519
LP3891EMRX-1.5	CS065	2	38968	52	0	4402000	1	1249079519
LP3891EMRX-1.8	CS065	2	38968	52	0	4402000	1	1249079519
LP3891ES-1.2	CS065	2	38968	52	0	4402000	1	1249079519
LP3891ES-1.5	CS065	2	38968	52	0	4402000	1	1249079519
LP3891ES-1.8	CS065	2	38968	52	0	4402000	1	1249079519
LP3891ESX-1.2	CS065	2	38968	52	0	4402000	1	1249079519
LP3891ESX-1.5	CS065	2	38968	52	0	4402000	1	1249079519
LP3891ESX-1.8	CS065	2	38968	52	0	4402000	1	1249079519
LP3891ET-1.2	CS065	2	38968	52	0	4402000	1	1249079519
LP3891ET-1.5	CS065	2	38968	52	0	4402000	1	1249079519
LP3891ET-1.8	CS065	2	38968	52	0	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.

More Application Notes

Title	Size in Kbytes	Date
AN-1219: Application Note 1219 LP3985 MicroSMD‐5 Evaluation Board Instruction	36 Kbytes	10-May-04	Download

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[Information as of 8-Nov-2009]