LM2651 - 1.5A High Efficiency Switching Regulator

LM2651 - 1.5A High Efficiency Switching Regulator

Datasheet	Packaging	Samples & Pricing	Eval. Boards	Reliability	Design Tools	Reference Designs	Application Notes	Knowledge Base

Features

•	Ultra high efficiency up to 97%
•	High efficiency over a 1.5A to milliamperes load range
•	4V to 14V input voltage range
•	1.8V, 2.5V, 3.3V, or ADJ output voltage
•	Internal MOSFET switch with low R_DS(on) of 75m
•	300kHz fixed frequency internal oscillator
•	7µA shutdown current
•	Patented current sensing for current mode control
•	Input undervoltage lockout
•	Adjustable soft-start
•	Current limit and thermal shutdown
•	16-pin TSSOP package

General Description

The LM2651 switching regulator provides high efficiency power conversion over a 100:1 load range (1.5A to 15mA). More...

Applications

•	Personal digital assistants (PDAs)
•	Computer peripherals
•	Battery-powered devices
•	Handheld scanners
•	High efficiency 5V conversion

Typical Application

*click for larger image

Parameters Values

Output Current 1500 mA

Input Min Voltage 4 Volt

Input Max Voltage 14 Volt

Output Min 3.3, 1.24 Volt

Output Max 3.3, 13 Volt

Frequency Min 300 kHz

Frequency Max 300 kHz

Efficiency (peak) 97 %

On/Off Pin Yes

Error Flag No

SoftStart Yes

Sync Pin No

Inverting No

Flyback No

RegType Switching Regulator

Temperature Min -40 deg C

Temperature Max 125 deg C

Adjustable Output Yes, No

Adj Switch Frequency No

PWM Mode Current

Topology Synchronous Buck

Special Features Max. Iq at shutdown is 20uA over full temp range, 7uA typical

Step-Down Yes

Multiple Output Capability No

Output Voltage 3.3 Volt

Output Range 1.24V to 13V

Switching Frequency 300 kHz

Feedback Voltage Undefined Volt

Regulator Family Undefined

Synchronous Rectification Yes

Typical Performance

*click for larger image

WEBENCH Live Simulation!

LM2651
4.00 <=	V in Lower V	<=	V in Upper V	<= 14.00
V out	1.24 <=		V	<= 14.00
I out			A	<= 1.50
Ambient Temperature			°C	<= 100
What are WEBENCH® tools?

Also Recommended

LM20242▲	36V Vin 2A PWM Sync Buck Regulator
LM20323▲	36V Vin 3A PWM Sync Buck Regulator
LM2852▲	2A Synch Buck Regulator For Low Voltage Applications
LM2854▲	4A Synch Buck Regulator For Low Voltage Applications
LM3100▲	36V 1.5A Synchronous Buck Regulator
LM2650▲	3A Integrated Synchronous Regulator W/ Adj Frequency And Sync Pin
LM2653▲	More Features Including Pgood Flag W/ Adjustable Delay

Additional Resources

Online Seminars

Application Notes

Block Diagram

click for larger image

Datasheet

RoHS Compliance Information	Size in Kbytes	Date
LM2651 1.5A High Efficiency Synchronous Switching Regulator	631 Kbytes	18-Apr-05	Download
LM2651 1.5A High Efficiency Synchronous Switching Regulator (Japanese)	441 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

Qty

Qty

$US each

LM2651EVAL

1.5A High Efficiency Switching Regulator

Full production

N/A

Buy Now

1+

$30.00

1

8 weeks

N/A

LM2651MTC-1.8

16

NOPB

1

260

Lifetime buy

N/A

Buy Now

1K+

$1.85

rail
of
92

NSZXYTT
2651MTC
-1.8

6 weeks

500

LM2651MTC-2.5

16

NOPB
STD

1
1

260
260

Lifetime buy

N/A

Buy Now

1K+

$1.85

rail
of
92

NSZXYTT
2651MTC
-2.5

12 weeks

2000

LM2651MTC-3.3

16

NOPB
STD

1
1

260
260

Full production

N/A

Samples

Buy Now

1K+

$1.85

rail
of
92

NSZXYTT
2651MTC
-3.3

6 weeks

500

LM2651MTC-ADJ

16

NOPB
STD

1
1

260
260

Full production

N/A

Samples

Buy Now

1K+

$1.85

rail
of
92

NSZXYTT
2651MTC
-ADJ

12 weeks

3000

LM2651MTCX-1.8

16

NOPB

1

260

Lifetime buy

N/A

Buy Now

1K+

$1.85

reel
of
2500

NSZXYTT
2651MTC
-1.8

12 weeks

10000

LM2651MTCX-2.5

16

NOPB
STD

1
1

260
260

Lifetime buy

N/A

Buy Now

1K+

$1.85

reel
of
2500

NSZXYTT
2651MTC
-2.5

12 weeks

7500

LM2651MTCX-3.3

16

NOPB

1

260

Full production

N/A

Buy Now

1K+

$1.85

reel
of
2500

NSZXYTT
2651MTC
-3.3

8 weeks

7500

LM2651MTCX-ADJ

16

NOPB
STD

1
1

260
260

Full production

N/A

Buy Now

1K+

$1.85

reel
of
2500

NSZXYTT
2651MTC
-ADJ

6 weeks

5000

LM2651-3.3EVAL

1.5A High Efficiency Switching Regulator

Full production

N/A

Buy Now

1+

$24.70

1

8 weeks

N/A

Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM2651MTC-1.8	LM2651MTC-ADJ	National Semiconductor	30 Nov 2009
LM2651MTC-2.5	LM2651MTC-ADJ	National Semiconductor	30 Nov 2009
LM2651MTCX-1.8	LM2651MTC-ADJ	National Semiconductor	30 Nov 2009
LM2651MTCX-2.5	LM2651MTCX-ADJ	National Semiconductor	30 Nov 2009

General Description

The LM2651 switching regulator provides high efficiency power conversion over a 100:1 load range (1.5A to 15mA). This feature makes the LM2651 an ideal fit in battery-powered applications that demand long battery life in both run and standby modes.

Synchronous rectification is used to achieve up to 97% efficiency. At light loads, the LM2651 enters a low power hysteretic or "sleep" mode to keep the efficiency high. In many applications, the efficiency still exceeds 80% at 15mA load. A shutdown pin is available to disable the LM2651 and reduce the supply current to less than 10µA.

The LM2651 contains a patented current sensing circuitry for current mode control. This feature eliminates the external current sensing resistor required by other current-mode DC-DC converters.

The LM2651 has a 300 kHz fixed frequency internal oscillator. The high oscillator frequency allows the use of extremely small, low profile components.

A programmable soft-start feature limits current surges from the input power supply at start up and provides a simple means of sequencing multiple power supplies.

Other protection features include input undervoltage lockout, current limiting, and thermal shutdown.

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM2651MTC-1.8	ABCD150	0	34175	0	0	4234000	1	1201409060
LM2651MTC-2.5	ABCD150	0	34175	0	0	4234000	1	1201409060
LM2651MTC-3.3	ABCD150	0	34175	0	0	4234000	1	1201409060
LM2651MTC-ADJ	ABCD150	0	34175	0	0	4234000	1	1201409060
LM2651MTCX-1.8	ABCD150	0	34175	0	0	4234000	1	1201409060
LM2651MTCX-2.5	ABCD150	0	34175	0	0	4234000	1	1201409060
LM2651MTCX-3.3	ABCD150	0	34175	0	0	4234000	1	1201409060
LM2651MTCX-ADJ	ABCD150	0	34175	0	0	4234000	1	1201409060

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
Power Reference Design Library			View

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Reference Designs

•	LM2651 Reference Design - Synchronous Triple Output Converter for Point Of Load Applications: 13.5V Input, 1.8V @ 1.5A; 3.3V @ 2A, 2.5V @ 0.1A Outputs

Application Notes

Title	Size in Kbytes	Date
AN-1143: Application Note 1143 LM2651_3.3V_EVAL 1.5A High Efficiency Synchronous Switching Regulator Evaluation Board	150 Kbytes	24-Jul-08	Download

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More Application Notes

Title	Size in Kbytes	Date
AN-1147: Application Note 1147 LM2651_EVAL 1.5A High Efficiency Synchronous Switching Regulator Evaluation Board	149 Kbytes	2-Oct-07	Download
AN-1133: Application Note 1133 LM2653EVAL 1.5A Synchronous Switching Regulator Evaluation Board	76 Kbytes	4-Oct-04	Download
AN-1215: Application Note 1215 LM2655 2.5A Synchronous Switching Regulator Evaluation Board	307 Kbytes	10-May-04	Download
AN-1520: Application Note 1520 A Guide to Board Layout for Best Thermal Resistance for Exposed Packages	2176 Kbytes	7-Sep-06	Download
AN-1520 (Chinese): Application Note 1520 A Guide to Board Layout for Best Thermal Resistance for Exposed Packages	849 Kbytes
AN-1071: Application Note 1071 Information About the LM2650 Evaluation Board Rev. 1	105 Kbytes	4-Oct-04	Download
AN-1071 (Japanese): Application Note 1071 Information About the LM2650 Evaluation Board Rev. 1	279 Kbytes

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[Information as of 8-Nov-2009]