HOME HOME SELECT DESIGN BUY EXPLORE About Us Support My Profile Search

 Products > Analog - Regulators > SwitchingRegulators > LM2679

LM2679  Product Folder

SIMPLE SWITCHER 5A Step-Down Voltage Regulator with Adjustable Current Limit
  

See Also:		   
LM2677 - FREQUENCY SYNCHRONIZATION PIN (UP TO 400KHZ)
     LM3477 - 500KHZ BUCK REGULATOR CONTROLLER
     LM2642 - SYNCHRONOUS BUCK CONTROLLER (UP TO 40A OUTPUT)
Generic P/N 2679
General
Description		 Features Datasheet Package
& Models		 Samples
& Pricing		 Reliability
Metrics		 Design
Tools		 Application
Notes

WEBENCH Live Simulation!
LM2679 Webench™ Custom
Design/Analyze/Build It
 
8.0 <=		 V in Lower
V		  
<=		 V in Upper
V		  
<= 40.0
V out 1.2 <= V <= 40.0
I out   A <= 5.00
Ambient Temperature °C <= 100

What is Webench?
  
Parametric Table
Temperature Min (deg C) -40 
Temperature Max (deg C) 125 
Multiple Output Capability No 
On/Off Pin No 
Error Flag No 
InputMin Voltage (Volt) 8, 15 
InputMax Voltage (Volt) 40 
Output Current (mA) 5000 
Output Voltage (Volt) 5, 12, 3.30 
Adjustable Output No, Yes 
Output Range 1.2V-37V 
Switching Frequency (Hz) 260000 
Adj Switch Frequency No 
Sync Pin No 
Efficiency (%) 84, 92, 82 
Flyback No 
Step-Up No 
Step-Down Yes 
RegType Switching Regulator 
-

Datasheet

TitleSize in KbytesDate
View Online
Download
Receive via Email
LM2679 SIMPLE SWITCHER 5A Step-Down Voltage Regulator with Adjustable Current Limit 457 Kbytes 15-Oct-03 View Online Download Receive via Email
LM2679 SIMPLE SWITCHER 5A Step-Down Voltage Regulator with Adjustable Current Limit (JAPANESE)
 259 Kbytes   View Online Download Receive via Email

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

Package Availability, Models, Samples & Pricing

Part NumberPackageStatusModelsSamples &
Electronic
Orders		Budgetary PricingStd
Pack
Size		Package
Marking
TypePinsMSL/Lead-Free AvailabilityLead
Time		QtySPICEIBISQty$US each
LM2679-5.0EVALevaluation boardFull productionN/AN/A 
Buy Now		1+$20.001-
N/A0
LM2679LD-12LLP14StatusLifetime buyN/AN/A 
Buy Now		1K+$3.14reel
of
250		NS
UZXYTT
S0000VB
13-15 weeks50000
LM2679LD-3.3LLP14StatusLifetime buyN/AN/A 
Buy Now		1K+$3.14reel
of
250		NS
UZXYTT
S0000TB
13-15 weeks50000
LM2679LD-5.0LLP14StatusLifetime buyN/AN/A 
Buy Now		1K+$3.14reel
of
250		NS
UZXYTT
S0000UB
13-15 weeks50000
LM2679LD-ADJLLP14StatusLifetime buyN/AN/A 
Buy Now		1K+$3.14reel
of
250		NS
UZXYTT
S0000XB
13-15 weeks50000
LM2679LDX-12LLP14StatusLifetime buyN/AN/A 1K+$3.14reel
of
2500		NS
UZXYTT
S0000VB
13-15 weeks50000
LM2679LDX-3.3LLP14StatusLifetime buyN/AN/A 1K+$3.14reel
of
2500		NS
UZXYTT
S0000TB
13-15 weeks50000
LM2679LDX-5.0LLP14StatusLifetime buyN/AN/A 1K+$3.14reel
of
2500		NS
UZXYTT
S0000UB
13-15 weeks50000
LM2679LDX-ADJLLP14StatusLifetime buyN/AN/A 1K+$3.14reel
of
2500		NS
UZXYTT
S0000XB
13-15 weeks50000
LM2679SD-12LLP14StatusFull productionN/AN/ASamples  reel
of
N/A		NS
UZXYTT
S0003FB
10-12 weeks20000
LM2679SD-3.3LLP14StatusFull productionN/AN/ASamples  reel
of
N/A		NS
UZXYTT
S0003HB
10-12 weeks20000
LM2679SD-5.0LLP14StatusFull productionN/AN/ASamples  reel
of
N/A		NS
UZXYTT
S0003JB
10-12 weeks25000
LM2679SD-ADJLLP14StatusFull productionN/AN/ASamples  reel
of
N/A		NS
UZXYTT
S0003KB
13-15 weeks20000
LM2679SDX-12LLP14StatusFull productionN/AN/A   reel
of
N/A		NS
UZXYTT
S0003FB
10-12 weeks20000
LM2679SDX-3.3LLP14StatusFull productionN/AN/A   reel
of
N/A		NS
UZXYTT
S0003HB
10-12 weeks20000
LM2679SDX-5.0LLP14StatusFull productionN/AN/A   reel
of
N/A		NS
UZXYTT
S0003JB
10-12 weeks25000
LM2679SDX-ADJLLP14StatusFull productionN/AN/A   reel
of
N/A		NS
UZXYTT
S0003KB
13-15 weeks20000
LM2679T-12TO 2207StatusFull productionN/AN/A24 Hour Samples
Buy Now 		1K+$3.14rail
of
45		NSUZXYTT
LM2679
T-12
13-15 weeks75000
LM2679T-3.3TO 2207StatusFull productionN/AN/A24 Hour Samples
Buy Now 		1K+$3.14rail
of
45		NSUZXYTT
LM2679
T-3.3
13-15 weeks75000
LM2679T-5.0TO 2207StatusFull productionN/AN/A24 Hour Samples
Buy Now 		1K+$3.14rail
of
45		NSUZXYTT
LM2679
T-5.0
13-15 weeks75000
LM2679T-ADJTO 2207StatusFull productionN/AN/A24 Hour Samples
Buy Now 		1K+$3.14rail
of
45		NSUZXYTT
LM2679
T-ADJ
13-15 weeks75000
LM2679S-12TO 2637StatusFull productionN/AN/A24 Hour Samples
Buy Now 		1K+$3.14rail
of
45		NSUZXYTT
LM2679
S-12
10-12 weeks20000
LM2679S-3.3TO 2637StatusFull productionN/AN/A24 Hour Samples
Buy Now 		1K+$3.14rail
of
45		NSUZXYTT
LM2679
S-3.3
10-12 weeks20000
LM2679S-5.0TO 2637StatusFull productionN/AN/ASamples
Buy Now 		1K+$3.14rail
of
45		NSUZXYTT
LM2679
S-5.0
10-12 weeks25000
LM2679S-ADJTO 2637StatusFull productionN/AN/A24 Hour Samples
Buy Now 		1K+$3.14rail
of
45		NSUZXYTT
LM2679
S-ADJ
13-15 weeks20000
LM2679SX-12TO 2637StatusFull productionN/AN/A 1K+$3.14reel
of
500		NSUZXYTT
LM2679
S-12
10-12 weeks20000
LM2679SX-3.3TO 2637StatusFull productionN/AN/A 1K+$3.14reel
of
500		NSUZXYTT
LM2679
S-3.3
10-12 weeks20000
LM2679SX-5.0TO 2637StatusFull productionN/AN/A 1K+$3.14reel
of
500		NSUZXYTT
LM2679
S-5.0
10-12 weeks25000
LM2679SX-ADJTO 2637StatusFull productionN/AN/A 
Buy Now 		1K+$3.14reel
of
500		NSUZXYTT
LM2679
S-ADJ
13-15 weeks20000

General Description

The LM2679 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 5A 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 LM2679 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 LM2679 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.

Features

  • Efficiency up to 92%
  • Simple and easy to design with (using off-the-shelf external components)
  • Resistor programmable peak current limit over a range of 3A to 7A.
  • 120 m 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

Applications

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

Reliability Metrics

Part Number Process Early Failure Rate - Rejects Sample Size (EFR) PPM * Rel. Rejects Device Hours Long Term Failure Rates (FITS) MTTF
LM2679-5.0EVALLMDMOS09700004800006814846805
LM2679LD-12LMDMOS09700004800006814846805
LM2679LD-3.3LMDMOS09700004800006814846805
LM2679LD-5.0LMDMOS09700004800006814846805
LM2679LD-ADJLMDMOS09700004800006814846805
LM2679LDX-12LMDMOS09700004800006814846805
LM2679LDX-3.3LMDMOS09700004800006814846805
LM2679LDX-5.0LMDMOS09700004800006814846805
LM2679LDX-ADJLMDMOS09700004800006814846805
LM2679S-12LMDMOS09700004800006814846805
LM2679S-3.3LMDMOS09700004800006814846805
LM2679S-5.0LMDMOS09700004800006814846805
LM2679S-ADJLMDMOS09700004800006814846805
LM2679SD-12LMDMOS09700004800006814846805
LM2679SD-3.3LMDMOS09700004800006814846805
LM2679SD-5.0LMDMOS09700004800006814846805
LM2679SD-ADJLMDMOS09700004800006814846805
LM2679SDX-12LMDMOS09700004800006814846805
LM2679SDX-3.3LMDMOS09700004800006814846805
LM2679SDX-5.0LMDMOS09700004800006814846805
LM2679SDX-ADJLMDMOS09700004800006814846805
LM2679SX-12LMDMOS09700004800006814846805
LM2679SX-3.3LMDMOS09700004800006814846805
LM2679SX-5.0LMDMOS09700004800006814846805
LM2679SX-ADJLMDMOS09700004800006814846805
LM2679T-12LMDMOS09700004800006814846805
LM2679T-3.3LMDMOS09700004800006814846805
LM2679T-5.0LMDMOS09700004800006814846805
LM2679T-ADJLMDMOS09700004800006814846805

For more information on Reliablitity Metrics, please click here.


Design Tools

TitleSize in KbytesDate
View Online
Download
Receive via Email
SimpleSwitcher® DC-DC Converters Design Software 9 Kbytes 28-Jul-2003 View    

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

Application Notes

TitleSize in KbytesDate
View Online
Download
Receive via Email
AN-1135: Application Note 1135 LM267X 3A, 5A Evaluation Boards 1208 Kbytes 1-Oct-02 View Online Download Receive via Email
AN-1149: Application Note 1149 Layout Guidelines for Switching Power Supplies 113 Kbytes 26-Sep-02 View Online Download Receive via Email
AN-1187: Application Note 1187 Leadless Leadframe Package (LLP) 1463 Kbytes 26-Sep-03 View Online Download Receive via Email
Application Note 1187 Leadless Leadframe Package (LLP) (JAPANESE)
 5326 Kbytes   View Online Download Receive via Email
AN-1197: Application Note 1197 Selecting Inductors for Buck Converters 371 Kbytes 1-Oct-02 View Online Download Receive via Email
AN-1229: Application Note 1229 SIMPLE SWITCHER PCB Layout Guidelines 229 Kbytes 1-Oct-02 View Online Download Receive via Email
AN-1246: Application Note 1246 Stresses in Wide Input DC-DC Converters 272 Kbytes 26-Sep-02 View Online Download Receive via Email
AN-556: Application Note 556 Introduction to Power Supplies 159 Kbytes 25-Sep-02 View Online Download Receive via Email

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

[Information as of 15-Jan-2004]

Website Guide • About "Cookies" • National is QS 9000 Certified • Privacy/Security Statement • Contact Us/Feedback
Site Terms & Conditions of Use • Copyright 2003© National Semiconductor Corporation