LM2674LDX-3.3 National Semiconductor, LM2674LDX-3.3 Datasheet

LM2674LDX-3.3

Manufacturer Part Number
LM2674LDX-3.3
Description
Manufacturer
National Semiconductor
Datasheet

Specifications of LM2674LDX-3.3

Dc To Dc Converter Type
Step Down
Number Of Outputs
1
Pin Count
16
Input Voltage
40V
Output Voltage
3.3V
Switching Freq
275KHz
Output Current
500mA
Efficiency
86%
Package Type
LLP EP
Output Type
Fixed
Switching Regulator
Yes
Mounting
Surface Mount
Input Voltage (min)
8V
Operating Temp Range
-40C to 125C
Operating Temperature Classification
Automotive
Lead Free Status / Rohs Status
Not Compliant

Available stocks

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Manufacturer
Quantity
Price
Part Number:
LM2674LDX-3.3
Manufacturer:
HOLTEK
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Part Number:
LM2674LDX-3.3
Manufacturer:
NS/国半
Quantity:
20 000
© 2005 National Semiconductor Corporation
LM2674
SIMPLE SWITCHER
500 mA Step-Down Voltage Regulator
General Description
The LM2674 series of regulators are monolithic integrated
circuits built with a LMDMOS process. These regulators
provide all the active functions for a step-down (buck)
switching regulator, capable of driving a 500 mA load current
with excellent line and load regulation. These devices are
available in fixed output voltages of 3.3V, 5.0V, 12V, and an
adjustable output version.
Requiring a minimum number of external components, these
regulators are simple to use and include patented internal
frequency compensation (Patent Nos. 5,382,918 and
5,514,947) and a fixed frequency oscillator.
The LM2674 series operates at a switching frequency of
260 kHz, thus allowing smaller sized filter components than
what would be needed with lower frequency switching regu-
lators. Because of its very high efficiency (
per traces on the printed circuit board are the only heat
sinking needed.
A family of standard inductors for use with the LM2674 are
available from several different manufacturers. This feature
greatly simplifies the design of switch-mode power supplies
using these advanced ICs. Also included in the datasheet
are selector guides for diodes and capacitors designed to
work in switch-mode power supplies.
Other features include a guaranteed
output voltage within specified input voltages and output
load conditions, and
ternal shutdown is included, featuring typically 50 µA
stand-by current. The output switch includes current limiting,
as well as thermal shutdown for full protection under fault
conditions.
Typical Application
SIMPLE SWITCHER
Windows
®
is a registered trademark of Microsoft Corporation.
®
is a registered trademark of National Semiconductor Corporation.
±
10% on the oscillator frequency. Ex-
±
DS100041
1.5% tolerance on
®
>
90%), the cop-
Power Converter High Efficiency
To simplify the LM2674 buck regulator design procedure,
there exists computer design software, LM267X Made
Simple (version 6.0).
Features
n Efficiency up to 96%
n Available in SO-8, 8-pin DIP and LLP packages
n Computer Design Software LM267X Made Simple
n Simple and easy to design with
n Requires only 5 external components
n Uses readily available standard inductors
n 3.3V, 5.0V, 12V, and adjustable output versions
n Adjustable version output voltage range: 1.21V to 37V
n
n Guaranteed 500mA output load current
n 0.25Ω DMOS Output Switch
n Wide input voltage range: 8V to 40V
n 260 kHz fixed frequency internal oscillator
n TTL shutdown capability, low power standby mode
n Thermal shutdown and current limit protection
Typical Applications
n Simple High Efficiency (
n Efficient Pre-Regulator for Linear Regulators
n Positive-to-Negative Converter
(version 6.0)
conditions
Regulator
±
1.5% max output voltage tolerance over line and load
>
10004101
90%) Step-Down (Buck)
February 2005
www.national.com

Related parts for LM2674LDX-3.3

LM2674LDX-3.3 Summary of contents

Page 1

... The output switch includes current limiting, as well as thermal shutdown for full protection under fault conditions. Typical Application SIMPLE SWITCHER ® registered trademark of National Semiconductor Corporation. Windows ® registered trademark of Microsoft Corporation. © 2005 National Semiconductor Corporation Power Converter High Efficiency ® ...

Page 2

... ADJ ADJ DIP 12 3.3 5.0 ADJ www.national.com See NSC Package Drawing Number MO8A/N08E 10004138 Package Marking LM2674LD-12 S0009B LM2674LDX-12 S0009B LM2674LD-3.3 S000AB LM2674LDX-3.3 S000AB LM2674LD-5.0 S000BB LM2674LDX-5.0 S000BB LM2674LD-ADJ S000CB LM2674LDX-ADJ S000CB LM2674M-12 2674M-12 LM2674MX-12 2674M-12 LM2674M-3.3 2674M-3.3 LM2674MX-3.3 2674M-3.3 LM2674M-5 ...

Page 3

... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage ON/OFF Pin Voltage Switch Voltage to Ground Boost Pin Voltage Feedback Pin Voltage ESD Susceptibility Human Body Model (Note 2) Power Dissipation ...

Page 4

LM2674-ADJ (Continued) Symbol Parameter η Efficiency V = 12V All Output Voltage Versions Specifications with standard type face are for T ture Range. Unless otherwise specified, V sion, and I = 100 mA. LOAD Symbol Parameters DEVICE PARAMETERS ...

Page 5

Typical Performance Characteristics Normalized Output Voltage Efficiency Switch Current Limit 10004103 10004105 10004107 5 Line Regulation 10004104 Drain-to-Source Resistance 10004106 Operating Quiescent Current 10004108 www.national.com ...

Page 6

Typical Performance Characteristics Standby Quiescent Current ON/OFF Pin Current (Sourcing) Feedback Pin Bias Current www.national.com (Continued) 10004109 10004111 10004113 6 ON/OFF Threshold Voltage 10004110 Switching Frequency 10004112 Peak Switch Current 10004114 ...

Page 7

Typical Performance Characteristics Dropout Voltage — 3.3V Option Block Diagram * Active Inductor Patent Number 5,514,947 † Active Capacitor Patent Number 5,382,918 (Continued) Dropout Voltage — 5.0V Option 10004115 FIGURE 1. 7 10004116 10004117 www.national.com ...

Page 8

Typical Performance Characteristics (Circuit of Figure 2) Continuous Mode Switching Waveforms V = 20V 5V OUT LOAD L = 100 µ 100 µF, C OUT A: V Pin Voltage, 10 V/div Inductor ...

Page 9

Test Circuit and Layout Guidelines µF, 50V Tantalum, Sprague “199D Series” µF, 25V Tantalum, Sprague “595D Series” OUT D1 - 3.3A, 50V Schottky Rectifier, IR 30WQ05F µH Sumida #RCR110D-680L C ...

Page 10

LM2674 Series Buck Regulator Design Procedure (Fixed Output) PROCEDURE (Fixed Output Voltage Version) To simplify the buck regulator design procedure, National Semiconductor is making available computer design software to be used with the SIMPLE SWITCHER line of switching regulators. LM267X ...

Page 11

LM2674 Series Buck Regulator Design Procedure (Fixed Output) PROCEDURE (Fixed Output Voltage Version) The capacitor list contains through-hole electrolytic capacitors from four different capacitor manufacturers and surface mount tantalum capacitors from two different capacitor manufacturers recommended that both ...

Page 12

LM2674 Series Buck Regulator Design Procedure (Fixed Output) PROCEDURE (Fixed Output Voltage Version) A low ESR aluminum or tantalum bypass capacitor is needed between the input pin and ground to prevent large voltage transients from appearing at the input. This ...

Page 13

INDUCTOR VALUE SELECTION GUIDES FIGURE 4. LM2674-3.3 FIGURE 6. LM2674-12 (For Continuous Mode Operation) 10004126 10004128 13 10004127 FIGURE 5. LM2674-5.0 10004129 FIGURE 7. LM2674-ADJ www.national.com ...

Page 14

INDUCTOR VALUE SELECTION GUIDES Ind. Inductance Current Ref. Through (µH) (A) Desg. Hole L2 150 0.21 67143920 67144290 RL-5470-4 L3 100 0.26 67143930 67144300 RL-5470 0.32 67143940 67144310 L5 47 0.37 67148310 67148420 L6 33 0.44 67148320 67148430 ...

Page 15

INDUCTOR VALUE SELECTION GUIDES Surface Mount Output Inductance Voltage Sprague (µH) (V) 594D Series (µF/V) 22 120/6.3 33 120/6.3 47 68/10 3.3 68 120/6.3 100 120/6.3 150 120/6.3 22 100/16 33 68/10 47 68/10 5.0 68 100/16 100 100/16 150 ...

Page 16

INDUCTOR VALUE SELECTION GUIDES 20V 30V 40V 50V International Rectifier Corp. Motorola, Inc. General Instruments Corp. Diodes, Inc. FIGURE 14. RMS Current Ratings for Low ESR Electrolytic Capacitors (Typical) www.national.com (For Continuous Mode Operation) (Continued) 500mA Diodes 3A Diodes V ...

Page 17

INDUCTOR VALUE SELECTION GUIDES FIGURE 15. Recommended Application Voltage for AVX TPS and Sprague 594D Tantalum Chip Capacitors Derated for 85˚C. (For Continuous Mode Operation) (Continued) AVX TPS Recommended Voltage Application Voltage Rating +85˚C Rating 3.3 6 ...

Page 18

LM2674 Series Buck Regulator Design Procedure (Adjustable Output) PROCEDURE (Adjustable Output Voltage Version) To simplify the buck regulator design procedure, National Semiconductor is making available computer design software to be used with the SIMPLE SWITCHER line of switching regulators. LM267X ...

Page 19

LM2674 Series Buck Regulator Design Procedure (Adjustable Output) (Continued) PROCEDURE (Adjustable Output Voltage Version) B. Select an appropriate capacitor value and voltage rating, using the capacitor code, from the output capacitor selection table in Figure 17. There are two solid ...

Page 20

LM2674 Series Buck Regulator Design Procedure (Adjustable Output) (Continued) PROCEDURE (Adjustable Output Voltage Version) 5. Input Capacitor ( low ESR aluminum or tantalum bypass capacitor is needed between the input pin and ground to prevent large voltage ...

Page 21

LM2674 Series Buck Regulator Design Procedure (Adjustable Output) (Continued) Surface Mount Cap. Sprague AVX TPS Ref. Desg. 594D Series Series # (µF/V) (µF/V) C1 120/6.3 100/10 C2 120/6.3 100/10 C3 120/6.3 100/10 C4 68/10 100/10 C5 100/16 100/10 C6 100/16 ...

Page 22

Application Information TYPICAL SURFACE MOUNT PC BOARD LAYOUT, FIXED OUTPUT (4X SIZE µF, 25V, Solid Tantalum Sprague, “594D series” µF, 10V, Solid Tantalum Sprague, “594D series” OUT D1 - 1A, 40V Schottky Rectifier, ...

Page 23

Application Information Layout is very important in switching regulator designs. Rap- idly switching currents associated with wiring inductance can generate voltage transients which can cause problems. For minimal inductance and ground loops, the wires indicated by heavy lines (in Figure ...

Page 24

Physical Dimensions unless otherwise noted 8-Lead (0.150" Wide) Molded Small Outline Package, JEDEC www.national.com inches (millimeters) Order Number LM2674M-3.3, LM2674M-5.0, LM2674M-12 or LM2674M-ADJ NS Package Number M08A 24 ...

Page 25

Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 8-Lead (0.300" Wide) Molded Dual-In-Line Package Order Number LM2674N-3.3, LM2674N-5.0, LM2674N-12 or LM2674N-ADJ NS Package Number N08E 25 www.national.com ...

Page 26

... BANNED SUBSTANCE COMPLIANCE National Semiconductor manufactures products and uses packing materials that meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2. ...

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