LM2672M-ADJ/NOPB National Semiconductor, LM2672M-ADJ/NOPB Datasheet



Manufacturer Part Number
National Semiconductor
Step-Down (Buck)r

Specifications of LM2672M-ADJ/NOPB

Internal Switch(s)
Synchronous Rectifier
Number Of Outputs
Voltage - Output
1.21 ~ 37 V
Current - Output
Frequency - Switching
Voltage - Input
6.5 ~ 40 V
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
8-SOIC (3.9mm Width)
Primary Input Voltage
No. Of Outputs
Output Voltage
Output Current
No. Of Pins
Operating Temperature Range
-40°C To +125°C
MSL 1 - Unlimited
Filter Terminals
Rohs Compliant
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Power - Output
Other names

Available stocks

Part Number
Part Number:
8 000
© 2007 National Semiconductor Corporation
Step-Down Voltage Regulator with Features
General Description
The LM2672 series of regulators are monolithic integrated
circuits built with a LMDMOS process. These regulators pro-
vide all the active functions for a step-down (buck) switching
regulator, capable of driving a 1A 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
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), fixed frequency oscillator, external shutdown,
soft-start, and frequency synchronization.
The LM2672 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 (>90%), the copper
traces on the printed circuit board are the only heat sinking
A family of standard inductors for use with the LM2672 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 ±1.5% tolerance on out-
put voltage within specified input voltages and output load
conditions, and ±10% on the oscillator frequency. External
shutdown is included, featuring typically 50 μA stand-by cur-
rent. The output switch includes current limiting, as well as
thermal shutdown for full protection under fault conditions.
Typical Application
(Fixed Output Voltage Versions)
is a registered trademark of Microsoft Corporation.
is a registered trademark of National Semiconductor Corporation
Power Converter High Efficiency 1A
To simplify the LM2672 buck regulator design procedure,
there exists computer design software, LM267X Made Sim-
ple version 6.0.
Typical Applications
Efficiency up to 96%
Available in SO-8, 8-pin DIP and LLP packages
Computer Design Software LM267X Made Simple
version 6.0
Simple and easy to design with
Requires only 5 external components
Uses readily available standard inductors
3.3V, 5.0V, 12V, and adjustable output versions
Adjustable version output voltage range: 1.21V to 37V
±1.5% max output voltage tolerance over line and load
Guaranteed 1A output load current
0.25Ω DMOS Output Switch
Wide input voltage range: 8V to 40V
260 kHz fixed frequency internal oscillator
TTL shutdown capability, low power standby mode
Soft-start and frequency synchronization
Thermal shutdown and current limit protection
Simple High Efficiency (>90%) Step-Down (Buck)
Efficient Pre-Regulator for Linear Regulators
April 2007

LM2672M-ADJ/NOPB Summary of contents

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... The output switch includes current limiting, as well as thermal shutdown for full protection under fault conditions. Typical Application (Fixed Output Voltage Versions) SIMPLE SWITCHER ® registered trademark of National Semiconductor Corporation Windows ® registered trademark of Microsoft Corporation. © 2007 National Semiconductor Corporation ® ...

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... TABLE 1. Package Marking and Ordering Information Order Information Package Marking LM2672LD-12 LM2672LDX-12 LM2672LD-3.3 LM2672LDX-3.3 LM2672LD-5.0 LM2672LDX-5.0 LM2672LD-ADJ LM2672LDX-ADJ LM2672M-12 LM2672MX-12 LM2672M-3.3 LM2672MX-3.3 LM2672M-5.0 LM2672MX-5.0 LM2672M-ADJ 2672M-ADJ LM2672MX-ADJ 2672M-ADJ LM2672N-12 LM2672N-12 LM2672N-3.3 LM2672N-3.3 LM2672N-5.0 LM2672N-5.0 LM2672N-ADJ LM2672N-ADJ 2 8-Lead Package Top View 1293402 ...

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... 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 Electrical Characteristics LM2672-3 ...

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All Output Voltage Versions Specifications with standard type face are for T Range. Unless otherwise specified 100 mA. LOAD Symbol Parameters DEVICE PARAMETERS I Quiescent Current Q I Standby Quiescent Current STBY I Current Limit CL I ...

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Typical Performance Characteristics Normalized Output Voltage Efficiency Switch Current Limit 1293403 1293405 1293407 5 Line Regulation 1293404 Drain-to-Source Resistance 1293406 Operating Quiescent Current 1293408 www.national.com ...

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Standby Quiescent Current ON/OFF Pin Current (Sourcing) Feedback Pin Bias Current www.national.com 1293409 Switching Frequency 1293411 Peak Switch Current 1293413 6 ON/OFF Threshold Voltage 1293410 1293412   1293414 ...

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Dropout Voltage—3.3V Option Block Diagram * Patent Number 5,514,947 † Patent Number 5,382,918 Dropout Voltage—5.0V Option 1293415 FIGURE 1. 7 1293416 1293417 www.national.com ...

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Typical Performance Characteristics Continuous Mode Switching Waveforms V = 20V 5V OUT μ μF, C OUT A: V Pin Voltage, 10 V/div Inductor Current, 0.5 A/div C: Output ...

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Test Circuit and Layout Guidelines - 22 μF, 50V Tantalum, Sprague “199D Series” μF, 25V Tantalum, Sprague “595D Series” C OUT D1 - 3.3A, 50V Schottky Rectifier, IR 30WQ05F μH Sumida #RCR110D-680L - ...

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LM2672 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 ...

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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 the manufacturers and the manufacturer's series that are ...

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PROCEDURE (Fixed Output Voltage Version) 5. Boost Capacitor ( This capacitor develops the necessary voltage to turn the switch gate on fully. All applications should use a 0.01 μF, 50V ceramic capacitor. 6. Soft-Start Capacitor (C - optional) ...

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Inductor Value Selection Guides (For Continuous Mode Operation) FIGURE 4. LM2672-3.3 FIGURE 5. LM2672-5.0 Inductanc Ind. Current e Ref. Through (A) Desg. (μH) Hole L4 68 0.32 67143940 67144310 L5 47 0.37 67148310 67148420 L6 33 0.44 67148320 67148430 L7 ...

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Inductanc Ind. Current e Ref. Through (A) Desg. (μH) Hole L24 22 1.70 67148370 67148480 L27 220 1.00 67144110 67144490 L28 150 1.20 67144120 67144500 L29 100 1.47 67144130 67144510 L30 68 1.78 67144140 67144520 Coilcraft Inc. Coilcraft Inc., Europe ...

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FIGURE 10. Output Capacitor Table Phone (847) 843-7500 Nichicon Corp. FAX (847) 843-2798 Panasonic Phone (714) 373-7857 FAX (714) 373-7102 AVX Corp. Phone (803) 448-9411 FAX (803) 448-1943 Phone (207) 324-4140 Sprague/Vishay FAX (207) 324-7223 Sanyo Corp. Phone (619) 661-6322 ...

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FIGURE 14. RMS Current Ratings for Low ESR Electrolytic Capacitors (Typical) FIGURE 15. Recommended Application Voltage for AVX TPS and Sprague 594D Tantalum Chip Capacitors Derated for 85°C. www.national.com 1293433 AVX TPS Recommended Voltage Application Voltage Rating +85°C Rating 3.3 ...

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LM2672 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 ...

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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 tantalum (surface mount) capacitor manufacturers and four electrolytic (through ...

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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 transients from appearing at the input. This capacitor should ...

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Surface Mount Cap. Sprague Ref. Desg. 594D Series # (μF/V) C1 120/6.3 C2 120/6.3 C3 120/6.3 C4 68/10 C5 100/16 C6 100/16 C7 68/10 C8 100/16 C9 100/16 C10 100/16 C11 100/16 C12 100/16 C13 100/16 C14 100/16 C15 47/20 ...

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Application Information TYPICAL SURFACE MOUNT PC BOARD LAYOUT, FIXD OUTPUT (4X SIZE μF, 50V, Solid Tantalum Sprague, “594D series” μF, 16V, Solid Tantalum Sprague, “594D series” C OUT D1 - 1A, 40V Schottky Rectifier, ...

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LLP PACKAGE DEVICES The LM2672 is offered in the 16 lead LLP surface mount package to allow for increased power dissipation compared to the SO-8 and DIP. www.national.com The Die Attach Pad (DAP) can and should be connected to PCB ...

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... Physical Dimensions inches (millimeters) unless otherwise noted 8-Lead (0.150 Wide) Molded Small Outline Package, JEDEC Order Number LM2672M-3.3, LM2672M-5.0, LM2672M-12 or LM2672M-ADJ NS Package Number M08A 23 www.national.com ...

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Wide) Molded Dual-In-Line Package Order Number LM2672N-3.3, LM2672N-5.0, LM2672N-12 or LM2672N-ADJ NS Package Number N08E 16-Lead LLP Surface Mount Package NS Package Number LDA16A 24 ...

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25 www.national.com ...

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... National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other brand or product names may be trademarks or registered trademarks of their respective holders. ...

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