LM1085 - 3A Low Dropout Positive Regulators

LM1085 - 3A Low Dropout Positive Regulators

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

Features

Available in 3.3V, 5.0V, 12V and Adjustable Versions
Current Limiting and Thermal Protection

Output Current	3A
Line Regulation	0.015% (typical)
Load Regulation	0.1% (typical)

General Description

The LM1085 is a series of low dropout positive voltage regulators with a maximum dropout of 1.5V at 3A of load current. More...

Applications

•	High Efficiency Linear Regulators
•	Battery Charger
•	Post Regulation for Switching Supplies
•	Constant Current Regulator
•	Microprocessor Supply

Typical Application

click for larger image

Parameters Values

Output Current 3000 mA

Output Min 3.3, 1.25, 12, 5 Volt

Input Min Voltage 2.6 Volt

Input Max Voltage 25, 27, 18, 29 Volt

Dropout Voltage 1.3 Volt

Adjustable Output No

Quiescent Current 5 mA

On/Off Pin No

Error Flag No

RegType LDO

Temperature Min -40 deg C

Temperature Max 125 deg C

Output Max 3.3, 27.5, 12, 5 Volt

Output Voltage 3.3, 12, 5 Volt

Typical Performance

click for larger image

Also Recommended

LP38513▲	New! National's LP38k Family Of High
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LP38859▲	See More At LDO.NATIONAL.COM

Additional Resources

Application Notes

Connection Diagram

click for larger image

Datasheet

RoHS Compliance Information	Size in Kbytes	Date
LM1085 3A Low Dropout Positive Regulators	744 Kbytes	6-Jun-05	Download
LM1085 3A Low Dropout Positive Regulators (Japanese)	537 Kbytes

If you have trouble printing or viewing PDF file(s), see Printing Problems.

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

LM1085IT-12

3

NOPB
STD

1
1

NA
NA

Full production

N/A

Buy Now

1K+

$1.03

rail
of
45

NSUZXYTTE#
LM1085
IT-12

8 weeks

1000

LM1085IT-3.3

3

NOPB
STD

1
1

NA
NA

Full production

N/A

Samples

Buy Now

1K+

$1.03

rail
of
45

NSUZXYTTE#
LM1085
IT-3.3

8 weeks

500

LM1085IT-5.0

3

NOPB
STD

1
1

NA
NA

Full production

N/A

Samples

Buy Now

1K+

$1.03

rail
of
45

NSUZXYTTE#
LM1085
IT-5.0

8 weeks

500

LM1085IT-ADJ

3

NOPB
STD

1
1

NA
NA

Full production

N/A

Samples

Buy Now

1K+

$1.03

rail
of
45

NSUZXYTTE#
LM1085
IT-ADJ

6 weeks

5000

LM1085IS-12

3

NOPB
STD

3
3

245
235

Full production

N/A

Buy Now

1K+

$1.09

rail
of
45

NSUZXYTTE#
LM1085
IS-12

8 weeks

1000

LM1085IS-3.3

3

NOPB
STD

3
3

245
235

Full production

N/A

Samples

Buy Now

1K+

$1.09

rail
of
45

NSUZXYTTE#
LM1085
IS-3.3

8 weeks

1000

LM1085IS-5.0

3

NOPB
STD

3
3

245
235

Full production

N/A

Samples

Buy Now

1K+

$1.09

rail
of
45

NSUZXYTTE#
LM1085
IS-5.0

8 weeks

1000

LM1085IS-ADJ

3

NOPB
STD

3
3

245
235

Full production

N/A

Samples

Buy Now

1K+

$1.09

rail
of
45

NSUZXYTTE#
LM1085
IS-ADJ

12 weeks

1000

LM1085ISX-12

3

NOPB
STD

3
3

245
235

Lifetime buy

N/A

Buy Now

1K+

$1.09

reel
of
500

NSUZXYTTE#
LM1085
IS-12

8 weeks

2000

LM1085ISX-3.3

3

NOPB
STD

3
3

245
235

Full production

N/A

Buy Now

1K+

$1.09

reel
of
500

NSUZXYTTE#
LM1085
IS-3.3

8 weeks

1000

LM1085ISX-5.0

3

NOPB
STD

3
3

245
235

Full production

N/A

Buy Now

1K+

$1.09

reel
of
500

NSUZXYTTE#
LM1085
IS-5.0

8 weeks

2000

LM1085ISX-ADJ

3

NOPB
STD

3
3

245
235

Full production

N/A

Buy Now

1K+

$1.09

reel
of
500

NSUZXYTTE#
LM1085
IS-ADJ

12 weeks

15000

LM1085I-3.3 MDC

Lifetime buy

N/A

tray
of
N/A

6 weeks

N/A

LM1085I-ADJ MDC

Full production

N/A

tray
of
N/A

8 weeks

7500

Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM1085I-3.3 MDC	LM1085I-ADJ MDC	NATIONAL SEMICONDUCTOR	01 Dec 2009
LM1085ISX-12	LM1085IS-ADJ	NATIONAL SEMICONDUCTOR	01 Dec 2009

General Description

The LM1085 is a series of low dropout positive voltage regulators with a maximum dropout of 1.5V at 3A of load current. It has the same pin-out as National Semiconductor's industry standard LM317.

The LM1085 is available in an adjustable version, which can set the output voltage with only two external resistors. It is also available in three fixed voltages: 3.3V, 5.0V and 12.0V. The fixed versions integrate the adjust resistors.

The LM1085 circuit includes a zener trimmed bandgap reference, current limiting and thermal shutdown.

The LM1085 series is available in TO-220 and TO-263 packages. Refer to the LM1084 for the 5A version, and the LM1086 for the 1.5A version.

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM1085I-3.3 MDC	LB300	0	33664	0	0	3830500	1	1086914834
LM1085I-ADJ MDC	LB300	0	33664	0	0	3830500	1	1086914834
LM1085IS-12	LB300	0	33664	0	0	3830500	1	1086914834
LM1085IS-3.3	LB300	0	33664	0	0	3830500	1	1086914834
LM1085IS-5.0	LB300	0	33664	0	0	3830500	1	1086914834
LM1085IS-ADJ	LB300	0	33664	0	0	3830500	1	1086914834
LM1085ISX-12	LB300	0	33664	0	0	3830500	1	1086914834
LM1085ISX-3.3	LB300	0	33664	0	0	3830500	1	1086914834
LM1085ISX-5.0	LB300	0	33664	0	0	3830500	1	1086914834
LM1085ISX-ADJ	LB300	0	33664	0	0	3830500	1	1086914834
LM1085IT-12	LB300	0	33664	0	0	3830500	1	1086914834
LM1085IT-3.3	LB300	0	33664	0	0	3830500	1	1086914834
LM1085IT-5.0	LB300	0	33664	0	0	3830500	1	1086914834
LM1085IT-ADJ	LB300	0	33664	0	0	3830500	1	1086914834

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
LM108X Qualification Package	1455 Kbytes	24-Jun-1999	View Online	Download

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Application Notes

Title	Size in Kbytes	Date
AN-1148: Application Note 1148 Linear Regulators: Theory Of Operation and Compensation	200 Kbytes	10-May-04	Download
AN-1148 (Japanese): Application Note 1148 Linear Regulators: Theory Of Operation and Compensation	216 Kbytes
AN-1148 (Chinese): Application Note 1148 Linear Regulators: Theory Of Operation and Compensation	396 Kbytes

If you have trouble printing or viewing PDF file(s), see Printing Problems.

More Application Notes

Title	Size in Kbytes	Date
AN-79: Application Note 79 IC Preamplifier Challenges Choppers on Drift	380 Kbytes	1-Oct-02	Download
AN-29: Application Note 29 IC Op Amp Beats FETs on Input Current	444 Kbytes	1-Oct-02	Download
AN-241: Application Note 241 Working with High Impedance Op Amps	130 Kbytes	4-Oct-04	Download
AN-173: Application Note 173 IC Zener Eases Reference Design	54 Kbytes	1-Oct-02	Download
AN-161: Application Note 161 IC Voltage Reference has 1 ppm per Degree Drift	138 Kbytes	10-Oct-02	Download
AN-222: Application Note 222 Super Matched Bipolar Transistor Pair Sets New Standards for Drift and Noise	399 Kbytes	1-Oct-02	Download
AN-178: Application Note 178 Applications for an Adjustable IC Power Regulator	40 Kbytes	3-Oct-02	Download
AN-30: Application Note 30 Log Converters	124 Kbytes	2-Oct-02	Download
AN-41: Application Note 41 Precision IC Comparator Runs from +5V Logic Supply	150 Kbytes	2-Oct-02	Download
AN-56: 1.2 Volt Reference	116 Kbytes	4-Nov-95	Download
AN-56 (Chinese): 1.2 Volt Reference	291 Kbytes

If you have trouble printing or viewing PDF file(s), see Printing Problems.

[Information as of 8-Nov-2009]