LM2670 - SIMPLE SWITCHER High Efficiency 3A Step-Down Voltage Regulator with Sync

	LM2670 - SIMPLE SWITCHER High Efficiency 3A Step-Down Voltage Regulator with Sync

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

Features

•	Efficiency up to 94%
•	Simple and easy to design with (using off-the-shelf external components)
•	150 mΩ DMOS output switch
•	3.3V, 5V and 12V fixed output and adjustable (1.2V to 37V ) versions
•	50μA standby current when switched OFF
•	±2%maximum output tolerance over full line and load conditions
•	Wide input voltage range: 8V to 40V
•	External Sync clock capability (280KHz to 400KHz)
•	260 KHz fixed frequency internal oscillator
•	−40 to +125°C operating junction temperature range

General Description

The LM2670 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
•	Communications and radio equipment regulator with synchronized clock frequency

Typical Application

click for larger image

Parametric Table expand

Parametric Table collapse

Output Current 3000 mA

Input Min Voltage 8 Volt

Input Max Voltage 40 Volt

Output Min 12 Volt

Output Max 12 Volt

Frequency Min 260 kHz

Frequency Max 260 kHz

Output Current 3000 mA

Input Min Voltage 8 Volt

Input Max Voltage 40 Volt

Output Min 12 Volt

Output Max 12 Volt

Frequency Min 260 kHz

Frequency Max 260 kHz

Efficiency (peak) 94 %

On/Off Pin Yes

Error Flag No

SoftStart No

Sync Pin Yes

Flyback No

RegType Switching Regulator

Temperature Min -40 deg C

Temperature Max 125 deg C

Adjustable Output No

Adj Switch Frequency No

PWM Mode Voltage with Vin Feedforward

Topology Buck

Special Features Internal Type 3 compensation, 2% output voltage accuracy, SIMPLE SWITCHER regulator

Step-Down Yes

Multiple Output Capability No

Output Power Undefined Watt

Output Voltage 12 Volt

Output Range 12V

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!

LM2670 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

LM22670	Wider Input Voltage Range (4.5V To 42V), Adjustable Switching Frequency Up To 1MHz
LM25576	For Ultra-Fast Transient Response
LM5576	Wider Input Voltage Range (6 To 75V) And Higher Switching Frequency (Up To 500kHz)

Additional Resources

Online Seminars

SIMPLE SWITCHER® Topologies and their Morphology

Design Tools (see below)

Application Notes (see below)

See Layout Guidelines

Block Diagram

click for larger image

Datasheet

RoHS Compliance Information	Size in Kbytes	Date
LM2670 SIMPLE SWITCHER High Efficiency 3A Step-Down Voltage Regulator with Sync	669 Kbytes	1-May-08	View Online Download
LM2670 SIMPLE SWITCHER High Efficiency 3A Step-Down Voltage Regulator with Sync (Japanese)	1081 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

LM2670SD-12

14

NOPB

1

260

Full production

N/A

1K+

$1.98

reel
of
250

NS
UZXYTT
S0002LB

6 weeks

2000

LM2670SD-3.3

14

NOPB

1

260

Full production

N/A

1K+

$1.98

reel
of
250

NS
UZXYTT
S0002NB

8 weeks

500

LM2670SD-5.0

14

NOPB

1

260

Full production

N/A

1K+

$1.98

reel
of
250

NS
UZXYTT
S0002PB

6 weeks

1000

LM2670SD-ADJ

14

NOPB

1

260

Full production

N/A

Samples

1K+

$1.98

reel
of
250

NS
UZXYTT
S0002RB

6 weeks

1000

LM2670SDX-12

14

Full production

N/A

1K+

$1.98

reel
of
2500

NS
UZXYTT
S0002LB

16 weeks

N/A

LM2670SDX-3.3

14

NOPB

1

260

Full production

N/A

1K+

$1.98

reel
of
2500

NS
UZXYTT
S0002NB

6 weeks

N/A

LM2670SDX-5.0

14

NOPB

1

260

Full production

N/A

1K+

$1.98

reel
of
2500

NS
UZXYTT
S0002PB

6 weeks

3000

LM2670SDX-ADJ

14

NOPB

1

260

Full production

N/A

1K+

$1.98

reel
of
2500

NS
UZXYTT
S0002RB

6 weeks

3000

LM2670T-12

7

NOPB

1

NA

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2670
T-12

6 weeks

2000

LM2670T-3.3

7

NOPB

1

NA

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2670
T-3.3

6 weeks

500

LM2670T-5.0

7

STD

NOPB

1

1

NA

NA

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2670
T-5.0

6 weeks

500

LM2670T-ADJ

7

NOPB

1

NA

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2670
T-ADJ

6 weeks

500

LM2670S-12

7

NOPB

3

245

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2670
S-12

6 weeks

500

LM2670S-3.3

7

NOPB

3

245

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2670
S-3.3

6 weeks

500

LM2670S-5.0

7

STD

NOPB

3

3

235

245

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2670
S-5.0

6 weeks

500

LM2670S-ADJ

7

STD

NOPB

3

3

235

245

Full production

N/A

Samples

1K+

$1.98

rail
of
45

NSUZXYTTE#
LM2670
S-ADJ

6 weeks

1000

LM2670SX-12

7

NOPB

3

245

Full production

N/A

1K+

$1.98

reel
of
500

NSUZXYTTE#
LM2670
S-12

6 weeks

N/A

LM2670SX-3.3

7

NOPB

3

245

Full production

N/A

1K+

$1.98

reel
of
500

NSUZXYTTE#
LM2670
S-3.3

6 weeks

1000

LM2670SX-5.0

7

NOPB

3

245

Full production

N/A

1K+

$1.98

reel
of
500

NSUZXYTTE#
LM2670
S-5.0

6 weeks

2000

LM2670SX-ADJ

7

STD

NOPB

3

3

235

245

Full production

N/A

1K+

$1.98

reel
of
500

NSUZXYTTE#
LM2670
S-ADJ

6 weeks

2000

Obsolete Parts

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM2670LD-12	LM2670SD-12	NATIONAL SEMICONDUCTOR	01/30/2004
LM2670LD-3.3	LM2670SD-3.3	NATIONAL SEMICONDUCTOR	01/30/2004
LM2670LD-5.0	LM2670SD-5.0	NATIONAL SEMICONDUCTOR	01/30/2004
LM2670LD-ADJ	LM2670SD-ADJ	NATIONAL SEMICONDUCTOR	01/30/2004
LM2670LDX-12	LM2670SDX-12	NATIONAL SEMICONDUCTOR	01/30/2004
LM2670LDX-3.3	LM2670SDX-3.3	NATIONAL SEMICONDUCTOR	01/30/2004
LM2670LDX-5.0	LM2670SDX-5.0	NATIONAL SEMICONDUCTOR	01/30/2004
LM2670LDX-ADJ	LM2670SDX-ADJ	NATIONAL SEMICONDUCTOR	01/30/2004
LM2670SX-ADJEP	NONE	NONE	11/16/2008

General Description

The LM2670 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. The switching clock frequency can be provided by an internal fixed frequency oscillator (260KHz) or from an externally provided clock in the range of 280KHz to 400Khz which allows the use of physically smaller sized components. A family of standard inductors for use with the LM2670 are available from several manufacturers to greatly simplify the design process. The external Sync clock provides direct and precise control of the output ripple frequency for consistent filtering or frequency spectrum positioning.

The LM2670 series also has built in thermal shutdown, current limiting and an ON/OFF control input that can power down the regulator to a low 50μA quiescent current standby condition. The output voltage is guaranteed to a ±2% tolerance.

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM *	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM2670S-12	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670S-3.3	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670S-5.0	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670S-ADJ	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670SD-12	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670SD-3.3	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670SD-5.0	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670SD-ADJ	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670SDX-12	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670SDX-3.3	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670SDX-5.0	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670SDX-ADJ	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670SX-12	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670SX-3.3	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670SX-5.0	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670SX-ADJ	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670T-12	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670T-3.3	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670T-5.0	LMDMOS	0	15190	0	0	1750000	3	496567278
LM2670T-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.

Design Tools

Title	Size in Kbytes	Date
Power Reference Design Library	0 Kbytes	28-Mar-2006	View

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Reference Designs

•	LM2670 Reference Design - Buck-Boost Inverter with Adjustable Dual Output: 11-16V Input, -7.44V @ 2A & 7.44V @ 2A Outputs

Application Notes

Title	Size in Kbytes	Date
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-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-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]