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

 Products > Analog - Regulators > SwitchingRegulators > LM2678

LM2678  Product Folder

SIMPLE SWITCHER High Efficiency 5A Step-Down Voltage Regulator
  

See Also:		   
LM2679 - Has Softstart and Adjustable Current Limit
     LM2677 - HAS FREQUENCY SYNCHRONIZATION AND SHUTDOWN
     LM3477 - 500 KHZ BUCK REGULATOR CONTROLLER (more design flexibility)
     LM2642 - SYNCHRONOUS BUCK CONTROLLER (UP TO 40A OUTPUT CURRENT, HIGH EFFICIENCY)
Generic P/N 2678
General
Description		 Features Datasheet Package
& Models		 Samples
& Pricing		 Reliability
Metrics		 Design
Tools		 Application
Notes

WEBENCH Live Simulation!
LM2678 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 Yes 
Error Flag No 
InputMin Voltage (Volt) 15, 8 
InputMax Voltage (Volt) 40 
Output Current (mA) 5000 
Output Voltage (Volt) 12, 3.30, 5 
Adjustable Output No, Yes 
Output Range 1.2V-37V 
Switching Frequency (Hz) 260000 
Adj Switch Frequency No 
Sync Pin No 
Efficiency (%) 92, 82, 84 
Flyback No 
Step-Up No 
Step-Down Yes 
RegType Switching Regulator 
-

Datasheet

TitleSize in KbytesDate
View Online
Download
Receive via Email
LM2678 SIMPLE SWITCHER High Efficiency 5A Step-Down Voltage Regulator 459 Kbytes 15-Oct-03 View Online Download Receive via Email
LM2678 SIMPLE SWITCHER High Efficiency 5A Step-Down Voltage Regulator (JAPANESE)
 249 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
LM2678LD-12LLP14StatusLifetime buyN/AN/A 
Buy Now		1K+$2.99reel
of
250		NS
UZXYTT
S0000RB
13-15 weeks50000
LM2678LD-3.3LLP14StatusLifetime buyN/AN/A 
Buy Now		1K+$2.99reel
of
250		NS
UZXYTT
S0000NB
13-15 weeks50000
LM2678LD-5.0LLP14StatusLifetime buyN/AN/A 
Buy Now 		1K+$2.99reel
of
250		NS
UZXYTT
S0000PB
13-15 weeks50000
LM2678LD-ADJLLP14StatusLifetime buyN/AN/A 1K+$2.99reel
of
250		NS
UZXYTT
S0000SB
13-15 weeks50000
LM2678LDX-12LLP14StatusLifetime buyN/AN/A 1K+$2.99reel
of
2500		NS
UZXYTT
S0000RB
13-15 weeks50000
LM2678LDX-3.3LLP14StatusLifetime buyN/AN/A 1K+$2.99reel
of
2500		NS
UZXYTT
S0000NB
13-15 weeks50000
LM2678LDX-5.0LLP14StatusLifetime buyN/AN/A 1K+$2.99reel
of
2500		NS
UZXYTT
S0000PB
13-15 weeks50000
LM2678LDX-ADJLLP14StatusLifetime buyN/AN/A 1K+$2.99reel
of
2500		NS
UZXYTT
S0000SB
13-15 weeks50000
LM2678SD-12LLP14StatusFull production N/AN/ASamples  reel
of
N/A		NS
UZXYTT
S0003BB
12-14 weeks100000
LM2678SD-3.3LLP14StatusFull production N/AN/ASamples  reel
of
N/A		NS
UZXYTT
S0003CB
8-10 weeks50000
LM2678SD-5.0LLP14StatusFull production N/AN/ASamples  reel
of
N/A		NS
UZXYTT
S0003DB
8-10 weeks25000
LM2678SD-ADJLLP14StatusFull production N/AN/ASamples  reel
of
N/A		NS
UZXYTT
S0003EB
12-14 weeks50000
LM2678SDX-12LLP14StatusFull production N/AN/A   reel
of
N/A		NS
UZXYTT
S0003BB
12-14 weeks100000
LM2678SDX-3.3LLP14StatusFull production N/AN/A   reel
of
N/A		NS
UZXYTT
S0003CB
8-10 weeks50000
LM2678SDX-5.0LLP14StatusFull production N/AN/A   reel
of
N/A		NS
UZXYTT
S0003DB
8-10 weeks25000
LM2678SDX-ADJLLP14StatusFull production N/AN/A   reel
of
N/A		NS
UZXYTT
S0003EB
12-14 weeks50000
LM2678T-12TO 2207StatusFull productionN/AN/ASamples
Buy Now 		1K+$2.99rail
of
45		NSUZXYTT
LM2678
T-12
13-15 weeks75000
LM2678T-3.3TO 2207StatusFull productionN/AN/A24 Hour Samples
Buy Now 		1K+$2.99rail
of
45		NSUZXYTT
LM2678
T-3.3
13-15 weeks75000
LM2678T-5.0TO 2207StatusFull productionN/AN/ASamples
Buy Now 		1K+$2.99rail
of
45		NSUZXYTT
LM2678
T-5.0
13-15 weeks75000
LM2678T-ADJTO 2207StatusFull productionN/AN/A24 Hour Samples
Buy Now 		1K+$2.99rail
of
45		NSUZXYTT
LM2678
T-ADJ
13-15 weeks75000
LM2678S-12TO 2637StatusFull productionN/AN/A24 Hour Samples
Buy Now 		1K+$2.99rail
of
45		NSUZXYTT
LM2678
S-12
12-14 weeks100000
LM2678S-3.3TO 2637StatusFull productionN/AN/A24 Hour Samples
Buy Now 		1K+$2.99rail
of
45		NSUZXYTT
LM2678
S-3.3
8-10 weeks50000
LM2678S-5.0TO 2637StatusFull productionN/AN/A24 Hour Samples
Buy Now 		1K+$2.99rail
of
45		NSUZXYTT
LM2678
S-5.0
4-6 weeks25000
LM2678S-ADJTO 2637StatusFull productionN/AN/A24 Hour Samples
Buy Now 		1K+$2.99rail
of
45		NSUZXYTT
LM2678
S-ADJ
12-14 weeks50000
LM2678SX-12TO 2637StatusFull productionN/AN/A 
Buy Now 		1K+$2.99reel
of
500		NSUZXYTT
LM2678
S-12
12-14 weeks100000
LM2678SX-3.3TO 2637StatusFull productionN/AN/A 
Buy Now		1K+$2.99reel
of
500		NSUZXYTT
LM2678
S-3.3
8-10 weeks25000
LM2678SX-5.0TO 2637StatusFull productionN/AN/A 
Buy Now 		1K+$2.99reel
of
500		NSUZXYTT
LM2678
S-5.0
8-10 weeks25000
LM2678SX-ADJTO 2637StatusFull productionN/AN/A 1K+$2.99reel
of
500		NSUZXYTT
LM2678
S-ADJ
12-14 weeks50000

General Description

The LM2678 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 LM2678 are available from several manufacturers to greatly simplify the design process.

The LM2678 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. 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)
  • 120 m 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
  • 260 KHz fixed frequency internal oscillator
  • -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
LM2678LD-12LMDMOS09700004800006814846805
LM2678LD-3.3LMDMOS09700004800006814846805
LM2678LD-5.0LMDMOS09700004800006814846805
LM2678LD-ADJLMDMOS09700004800006814846805
LM2678LDX-12LMDMOS09700004800006814846805
LM2678LDX-3.3LMDMOS09700004800006814846805
LM2678LDX-5.0LMDMOS09700004800006814846805
LM2678LDX-ADJLMDMOS09700004800006814846805
LM2678S-12LMDMOS09700004800006814846805
LM2678S-3.3LMDMOS09700004800006814846805
LM2678S-5.0LMDMOS09700004800006814846805
LM2678S-ADJLMDMOS09700004800006814846805
LM2678SD-12LMDMOS09700004800006814846805
LM2678SD-3.3LMDMOS09700004800006814846805
LM2678SD-5.0LMDMOS09700004800006814846805
LM2678SD-ADJLMDMOS09700004800006814846805
LM2678SDX-12LMDMOS09700004800006814846805
LM2678SDX-3.3LMDMOS09700004800006814846805
LM2678SDX-5.0LMDMOS09700004800006814846805
LM2678SDX-ADJLMDMOS09700004800006814846805
LM2678SX-12LMDMOS09700004800006814846805
LM2678SX-3.3LMDMOS09700004800006814846805
LM2678SX-5.0LMDMOS09700004800006814846805
LM2678SX-ADJLMDMOS09700004800006814846805
LM2678T-12LMDMOS09700004800006814846805
LM2678T-3.3LMDMOS09700004800006814846805
LM2678T-5.0LMDMOS09700004800006814846805
LM2678T-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-1157: Application Note 1157 Positive to Negative Buck-Boost Converter Using LM267X SIMPLE SWITCHER® Regulators 189 Kbytes 1-Oct-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