Voltage Regulator. LM2678T-12 Datasheet

LM2678T-12 Regulator. Datasheet pdf. Equivalent

LM2678T-12 Datasheet
Recommendation LM2678T-12 Datasheet
Part LM2678T-12
Description High Efficiency 5-A Step-Down Voltage Regulator
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LM2678
SNVS029K – MARCH 2000 – REVISED FEBRUARY 2017
LM2678 SIMPLE SWITCHER® High Efficiency 5-A Step-Down Voltage Regulator
1 Features
1 Efficiency Up to 92%
• Simple and Easy to Design Using Off-the-Shelf
External Components
• 120-mΩ DMOS Output Switch
• 3.3-V, 5-V, and 12-V Fixed Output and Adjustable
(1.2 V to 37 V) Versions
• 50-μA Standby Current When Switched OFF
• ±2% Maximum Output Tolerance Over Full Line
and Load Conditions
• Wide Input Voltage Range: 8 V to 40 V
• 260-kHz Fixed Frequency Internal Oscillator
40 to 125°C Operating Junction Temperature
Range
• Create a Custom Design Using the LM2678 With
the WEBENCH® Power Designer
2 Applications
• Simple-to-Design, High Efficiency (>90%) Step-
Down Switching Regulators
• Efficient System Preregulator for Linear Voltage
Regulators
• Battery Chargers
3 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 5-A 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 3.3 V, 5 V, and 12 V 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
(260 kHz) 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 50-
μA quiescent current standby condition. The output
voltage is ensured to a ±2% tolerance. The clock
frequency is controlled to within a ±11% tolerance.
Device Information(1)
PART NUMBER
PACKAGE
BODY SIZE (NOM)
TO-263 (7)
10.10 mm × 8.89 mm
LM2678
TO-220 (7)
14.986 mm × 10.16 mm
VSON (14)
6.00 mm × 5.00 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical Application
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.



Texas Instruments LM2678T-12
LM2678
SNVS029K – MARCH 2000 – REVISED FEBRUARY 2017
www.ti.com
Table of Contents
1 Features .................................................................. 1
2 Applications ........................................................... 1
3 Description ............................................................. 1
4 Revision History..................................................... 2
5 Pin Configuration and Functions ......................... 3
6 Specifications......................................................... 4
6.1 Absolute Maximum Ratings ...................................... 4
6.2 ESD Ratings.............................................................. 4
6.3 Recommended Operating Conditions....................... 4
6.4 Thermal Information .................................................. 5
6.5 Electrical Characteristics – 3.3 V .............................. 5
6.6 Electrical Characteristics – 5 V ................................. 5
6.7 Electrical Characteristics – 12 V ............................... 6
6.8 Electrical Characteristics – Adjustable...................... 6
6.9 Electrical Characteristics – All Output Voltage
Versions ..................................................................... 6
6.10 Typical Characteristics ............................................ 7
7 Detailed Description ............................................ 10
7.1 Overview ................................................................. 10
7.2 Functional Block Diagram ....................................... 10
7.3 Feature Description................................................. 10
7.4 Device Functional Modes........................................ 11
8 Application and Implementation ........................ 12
8.1 Application Information............................................ 12
8.2 Typical Application .................................................. 14
9 Power Supply Recommendations...................... 26
10 Layout................................................................... 26
10.1 Layout Guidelines ................................................. 26
10.2 Layout Example .................................................... 27
11 Device and Documentation Support ................. 28
11.1 Custom Design With WEBENCH® Tools ............. 28
11.2 Related Documentation......................................... 28
11.3 Receiving Notification of Documentation Updates 28
11.4 Community Resources.......................................... 28
11.5 Trademarks ........................................................... 28
11.6 Electrostatic Discharge Caution ............................ 28
11.7 Glossary ................................................................ 28
12 Mechanical, Packaging, and Orderable
Information ........................................................... 29
12.1 VSON Package Devices ....................................... 29
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision J (June 2016) to Revision K
Page
• Deleted RADJ = 5.6 kΩ .......................................................................................................................................................... 6
• Deleted and updated with new values for Min, Typ and Max ............................................................................................... 6
• Deleted and updated with new values for Min and Max ....................................................................................................... 6
• Changed soft-start pin to ON/OFF pin.................................................................................................................................... 6
• Changed to 200 µA from 1.5 mA............................................................................................................................................ 6
• Changed typ and max values to 16 and 15 mA ..................................................................................................................... 6
Changes from Revision I (April 2013) to Revision J
Page
• Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation
section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and
Mechanical, Packaging, and Orderable Information section. ................................................................................................. 1
• Removed all references to Computer Design Software LM267X Made Simple (Version 6.0).............................................. 1
Changes from Revision H (April 2013) to Revision I
Page
• Changed layout of National Data Sheet to TI format ........................................................................................................... 29
2
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Copyright © 2000–2017, Texas Instruments Incorporated



Texas Instruments LM2678T-12
www.ti.com
5 Pin Configuration and Functions
KTW Package
7-Pin TO-263
Top View
Not to scale
LM2678
SNVS029K – MARCH 2000 – REVISED FEBRUARY 2017
Not to scale
NDZ Package
7-Pin TO-220
Top View
7
6
5
4
3
2
1
ON/OFF
FB
NC
GND
CB
Input
Switch_output
NHM Package
14-Pin VSON
Top View
NC 1
Input 2
Input 3
CB 4
NC 5
NC 6
FB 7
14
13
12
DAP 11
10
9
8
Switch_output
Switch_output
Switch_output
NC
NC
GND
ON/OFF
DAP connect to pin 9
Not to scale
NAME
PIN
TO-263, TO-220
Switch output
1
VSON
12, 13, 14
Input
2
2, 3
CB
GND
3
4
4
9
FB
6
7
ON/OFF
NC
7
8
5
1, 5, 6, 10, 11
Pin Functions
I/O
DESCRIPTION
O
Source pin of the internal high-side FET. This is a switching node. Attached
this pin to an inductor and the cathode of the external diode.
Supply input pin to collector pin of high-side FET. Connect to power supply
I
and input bypass capacitors CIN. Path from VIN pin to high frequency bypass
CIN and GND must be as short as possible.
I
Boot-strap capacitor connection for high-side driver. Connect a high-quality
100-nF capacitor from CB to VSW Pin.
Power ground pins. Connect to system ground. Ground pins of CIN and
COUT. Path to CIN must be as short as possible.
Feedback sense input pin. Connect to the midpoint of feedback divider to set
I
VOUT for ADJ version or connect this pin directly to the output capacitor for a
fixed output version.
I
Enable input to the voltage regulator. High = ON and low = OFF. Pull this pin
high or float to enable the regulator.
— No connect pins.
Copyright © 2000–2017, Texas Instruments Incorporated
Product Folder Links: LM2678
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