LM2673 - 3A Step-Down Voltage Regulator with Adjustable Current Limit

	LM2673 - 3A Step-Down Voltage Regulator with Adjustable Current Limit

Datasheet	Packaging	Samples & Pricing	Eval. Boards	Reliability	Application Notes	Knowledge Base

Features

•	Efficiency up to 94%
•	Simple and easy to design with (using off-the-shelf external components)
•	Resistor programmable peak current limit over a range of 2A to 5A.
•	150 mΩ DMOS output switch
•	3.3V, 5V and 12V fixed output and adjustable (1.2V to 37V ) versions
•	±2%maximum output tolerance over full line and load conditions
•	Wide input voltage range: 8V to 40V
•	260 KHz fixed frequency internal oscillator
•	Softstart capability
•	−40 to +125°C operating junction temperature range

General Description

The LM2673 series of regulators are monolithic integrated circuits which provide all of the active functions for a step-down (buck) switching regulator capable of driving up to 3A loads with excellent line and load regulation characteristics. More...

Applications

•	Simple to design, high efficiency (>90%) step-down switching regulators
•	Efficient system pre-regulator for linear voltage regulators
•	Battery chargers

Typical Application

click for larger image

Parametric Table expand

Parametric Table collapse

Output Current 3000 mA

Input Min Voltage 8, 15 Volt

Input Max Voltage 40 Volt

Output Min 3.3, 1.23, 12, 5 Volt

Output Max 3.3, 37, 12, 5 Volt

Frequency Min 260 kHz

Frequency Max 260 kHz

Output Current 3000 mA

Input Min Voltage 8, 15 Volt

Input Max Voltage 40 Volt

Output Min 3.3, 1.23, 12, 5 Volt

Output Max 3.3, 37, 12, 5 Volt

Frequency Min 260 kHz

Frequency Max 260 kHz

Efficiency (peak) 88, 94, 86 %

On/Off Pin No

Error Flag No

SoftStart Yes

Sync Pin 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 Voltage with Vin Feedforward

Topology Buck

Special Features Programmable current limit, 2% output voltage accuracy, SIMPLE SWITCHER regulator

Step-Down Yes

Multiple Output Capability No

Output Power Undefined Watt

Output Voltage 3.3, Undefined, 12, 5 Volt

Output Range 5V, 12V, 1.23V to 37V, 3.3V

Switching Frequency 260 kHz

Regulator Family SIMPLE SWITCHER

AEC Q-100 Automotive Grade Undefined

Synchronous Rectification No

View Using Catalog

Typical Performance

*click for larger image

WEBENCH Live Simulation!

LM2673 WEBENCH® Custom Design/Analyze/Build It/Test It
8.00 <=	V in Lower V	<=	V in Upper V	<= 40.00
V out	1.21 <=		V	<= 40.00
I out			A	<= 3.00
Ambient Temperature			°C	<= 100
What are WEBENCH® tools?

Also Recommended

LM22673	Wider Input Voltage Range (4.5V To 42V), Fixed 500kHz
LM25576	Fast-Transient Response
LM5576	Up To 75V Vin, 3A Iout

Additional Resources

Application Notes (see below)

See Layout Guidelines

Block Diagram

click for larger image

Datasheet

RoHS Compliance Information	Size in Kbytes	Date
LM2673 SIMPLE SWITCHER 3A Step-Down Voltage Regulator with Adjustable Current Limit	667 Kbytes	29-Feb-08	View Online Download
LM2673 SIMPLE SWITCHER 3A Step-Down Voltage Regulator with Adjustable Current Limit (Japanese)	1109 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

LM2673-5.0EVAL

SIMPLE SWITCHER® 3A Step-Down Voltage Regulator with Adjustable Current Limit

Full production

N/A

1+

$30.00

1

8 weeks

N/A

LM2673SD-12

14

NOPB

1

260

Full production

N/A

1K+

$1.98

reel
of
250

NS
UZXYTT
S0002SB

6 weeks

500

LM2673SD-3.3

14

NOPB

1

260

Full production

N/A

Samples

1K+

$1.98

reel
of
250

NS
UZXYTT
S0002TB

6 weeks

1000

LM2673SD-5.0

14

STD

NOPB

1

1

260

260

Full production

N/A

1K+

$1.98

reel
of
250

NS
UZXYTT
S0002UB

6 weeks

2500

LM2673SD-ADJ

14

NOPB

1

260

Full production

N/A

Samples

1K+

$1.98

reel
of
250

NS
UZXYTT
S0002VB

6 weeks

500

LM2673SDX-12

14

Full production

N/A

1K+

$1.98

reel
of
2500

NS
UZXYTT
S0002SB

16 weeks

N/A

LM2673SDX-3.3

14

NOPB

1

260

Full production

N/A

1K+

$1.98

reel
of
2500

NS
UZXYTT
S0002TB

6 weeks

3000

LM2673SDX-5.0

14

NOPB

1

260

Full production

N/A

1K+

$1.98

reel
of
2500

NS
UZXYTT
S0002UB

6 weeks

3000

LM2673SDX-ADJ

14

NOPB

1

260

Full production

N/A

1K+

$1.98

reel
of
2500

NS
UZXYTT
S0002VB

6 weeks

3000

LM2673T-12

7

NOPB

1

NA

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2673
T-12

6 weeks

500

LM2673T-3.3

7

NOPB

1

NA

Full production

N/A

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2673
T-3.3

6 weeks

500

LM2673T-5.0

7

STD

NOPB

1

1

NA

NA

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2673
T-5.0

6 weeks

500

LM2673T-ADJ

7

STD

NOPB

1

1

NA

NA

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2673
T-ADJ

6 weeks

500

LM2673S-12

7

STD

NOPB

3

3

235

245

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2673
S-12

6 weeks

500

LM2673S-3.3

7

STD

NOPB

3

3

235

245

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2673
S-3.3

6 weeks

500

LM2673S-5.0

7

STD

NOPB

3

3

235

245

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2673
S-5.0

6 weeks

2000

LM2673S-ADJ

7

STD

NOPB

3

3

235

245

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2673
S-ADJ

6 weeks

500

LM2673SX-12

7

STD

NOPB

3

3

235

245

Full production

N/A

1K+

$1.98

reel
of
500

NSUZXYTTE#
LM2673
S-12

6 weeks

1000

LM2673SX-3.3

7

NOPB

3

245

Full production

N/A

1K+

$1.98

reel
of
500

NSUZXYTTE#
LM2673
S-3.3

6 weeks

2000

LM2673SX-5.0

7

STD

NOPB

3

3

235

245

Full production

N/A

1K+

$1.98

reel
of
500

NSUZXYTTE#
LM2673
S-5.0

6 weeks

1000

LM2673SX-ADJ

7

STD

NOPB

3

3

235

245

Full production

N/A

1K+

$1.98

reel
of
500

NSUZXYTTE#
LM2673
S-ADJ

6 weeks

2000

Obsolete Parts

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM2673LD-12	LM2673SD-12	NATIONAL SEMICONDUCTOR	01/30/2004
LM2673LD-3.3	LM2673SD-3.3	NATIONAL SEMICONDUCTOR	01/30/2004
LM2673LD-5.0	LM2673SD-5.0	NATIONAL SEMICONDUCTOR	01/30/2004
LM2673LD-ADJ	LM2673SD-ADJ	NATIONAL SEMICONDUCTOR	01/30/2004
LM2673LDX-12	LM2673SDX-12	NATIONAL SEMICONDUCTOR	01/30/2004
LM2673LDX-3.3	LM2673SDX-3.3	NATIONAL SEMICONDUCTOR	01/30/2004
LM2673LDX-5.0	LM2673SDX-5.0	NATIONAL SEMICONDUCTOR	01/30/2004
LM2673LDX-ADJ	LM2673SDX-ADJ	NATIONAL SEMICONDUCTOR	01/30/2004

General Description

The LM2673 series of regulators are monolithic integrated circuits which provide all of the active functions for a step-down (buck) switching regulator capable of driving up to 3A loads with excellent line and load regulation characteristics. High efficiency (>90%) is obtained through the use of a low ON-resistance DMOS power switch. The series consists of fixed output voltages of 3.3V, 5V and 12V and an adjustable output version.

The SIMPLE SWITCHER concept provides for a complete design using a minimum number of external components. A high fixed frequency oscillator (260KHz) allows the use of physically smaller sized components. A family of standard inductors for use with the LM2673 are available from several manufacturers to greatly simplify the design process.

Other features include the ability to reduce the input surge current at power-ON by adding a softstart timing capacitor to gradually turn on the regulator. The LM2673 series also has built in thermal shutdown and resistor programmable current limit of the power MOSFET switch to protect the device and load circuitry under fault conditions. The output voltage is guaranteed to a ±2% tolerance. The clock frequency is controlled to within a ±11% tolerance.

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM *	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM2673S-12	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673S-3.3	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673S-5.0	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673S-ADJ	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673SD-12	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673SD-3.3	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673SD-5.0	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673SD-ADJ	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673SDX-12	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673SDX-3.3	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673SDX-5.0	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673SDX-ADJ	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673SX-12	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673SX-3.3	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673SX-5.0	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673SX-ADJ	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673T-12	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673T-3.3	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673T-5.0	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2673T-ADJ	LMDMOS	0	15190	0	0	1750000	3	496567278

Note: The Early Failure Rates were calculated as point estimates. 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.

Application Notes

Title	Size in Kbytes	Date
AN-1157: Application Note 1157 Positive to Negative Buck-Boost Converter Using LM267X SIMPLE SWITCHER® Regulators	189 Kbytes	1-Oct-02	Download
AN-1157 (Japanese): Application Note 1157 Positive to Negative Buck-Boost Converter Using LM267X SIMPLE SWITCHER® Regulators	193 Kbytes
AN-1157 (Chinese): Application Note 1157 Positive to Negative Buck-Boost Converter Using LM267X SIMPLE SWITCHER® Regulators	307 Kbytes
AN-1135: Application Note 1135 LM267X 3A, 5A Evaluation Boards	1208 Kbytes	1-Oct-02	Download

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More Application Notes

Title	Size in Kbytes	Date
AN-1061: Application Note 1061 Power Conversion in Line-Powered Equipment	188 Kbytes	1-Oct-02	Download
AN-1061 (Japanese): Application Note 1061 Power Conversion in Line-Powered Equipment	215 Kbytes
AN-1120: Application Note 1120 LM2675-5.0EVAL 1A Step-Down High-Efficiency SIMPLE SWITCHER Evaluation Board	44 Kbytes	23-Sep-02	Download
AN-1229: Application Note 1229 SIMPLE SWITCHER PCB Layout Guidelines	229 Kbytes	1-Oct-02	Download
AN-1229 (Japanese): Application Note 1229 SIMPLE SWITCHER PCB Layout Guidelines	304 Kbytes
AN-1229 (Chinese): Application Note 1229 SIMPLE SWITCHER PCB Layout Guidelines	668 Kbytes

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[Information as of 21-Nov-2008]