Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - DC/DC voltage regulator Holder TO 263 7

Voltage

5V/5A

OUT

2 x 180 PF/16V

22 PH

Feedback

Boost

6TQ045S

Ground

Current

Softstart

1 nF

Voltage

8V to 40V

Input

LM2679 - 5.0

Output

Switch

Output

0.01 PF

Limit

Adjust

5.6k

0.47 PF

+++

3 x 15 PF/50V

37,125

ADJ

LM2679

www.ti.com

SNVS026N –MARCH 2000–REVISED APRIL 2013

LM2679 SIMPLE SWITCHER

5A Step-Down Voltage Regulator with Adjustable Current

Limit

Check for Samples: LM2679

FEATURES

DESCRIPTION

The LM2679 series of regulators are monolithic

• Efficiency Up to 92%

integrated circuits which provide all of the active

• Simple and Easy to Design with (Using Off-

functions for a step-down (buck) switching regulator

The-Shelf External Components)

capable of driving up to 5A loads with excellent line

• Resistor Programmable Peak Current Limit

and load regulation characteristics. High efficiency

(>90%) is obtained through the use of a low ON-

Over a Range of 3A to 7A.

resistance DMOS power switch. The series consists

• 120 mΩ DMOS Output Switch

of fixed output voltages of 3.3V, 5V and 12V and an

• 3.3V, 5V and 12V Fixed Output and Adjustable

adjustable output version.

(1.2V to 37V ) Versions

The SIMPLE SWITCHER

concept provides for a

• ±2% Maximum Output Tolerance Over Full

complete design using a minimum number of external

Line and Load Conditions

components. A high fixed frequency oscillator

• Wide Input Voltage Range: 8V to 40V

(260KHz) allows the use of physically smaller sized

components. A family of standard inductors for use

• 260 KHz Fixed Frequency Internal Oscillator

with the LM2679 are available from several

• Softstart Capability

manufacturers to greatly simplify the design process.

• −40 to +125°C Operating Junction Temperature

Other features include the ability to reduce the input

Range

surge current at power-ON by adding a softstart

timing capacitor to gradually turn on the regulator.

APPLICATIONS

The LM2679 series also has built in thermal

shutdown and resistor programmable current limit of

• Simple to Design, High Efficiency (>90%) Step-

the power MOSFET switch to protect the device and

Down Switching Regulators

load circuitry under fault conditions. The output

• Efficient System Pre-Regulator for Linear

voltage is specified to a ±2% tolerance. The clock

Voltage Regulators

frequency is controlled to within a ±11% tolerance.

• Battery Chargers

Typical Application

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2SIMPLE SWITCHER, Switchers Made Simple are registered trademarks of Texas Instruments.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (35 pages)

PAGE 1
LM2679 www.ti.com SNVS026N – MARCH 2000 – REVISED APRIL 2013 LM2679 SIMPLE SWITCHER® 5A Step-Down Voltage Regulator with Adjustable Current Limit Check for Samples: LM2679 FEATURES 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.
PAGE 2
LM2679 SNVS026N – MARCH 2000 – REVISED APRIL 2013 www.ti.com Connection Diagrams Figure 1. DDPAK Package Top View See Package Number KTW0007B Figure 2. TO-220 Package Top View See Package Number NDZ0007B * 1 14 VSW VIN 2 13 VSW VIN 3 12 VSW CB 4 11 * * 5 10 * 6 9 GND 7 8 CURRENT ADJ FB DAP** SOFTSTART * No Connections ** Connect to Pin 9 on PCB Figure 3. VSON-14 Top View See Package Number NHM0014A These devices have limited built-in ESD protection.
PAGE 3
LM2679 www.ti.com SNVS026N – MARCH 2000 – REVISED APRIL 2013 Operating Ratings Supply Voltage 8V to 40V −40°C to 125°C Junction Temperature Range (TJ) Electrical Characteristics LM2679-3.3 Limits appearing in bold type face apply over the entire junction temperature range of operation, −40°C to 125°C. Specifications appearing in normal type apply for TA = TJ = 25°C. RADJ = 5.6KΩ.
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LM2679 SNVS026N – MARCH 2000 – REVISED APRIL 2013 www.ti.com All Output Voltage Versions Electrical Characteristics Limits appearing in bold type face apply over the entire junction temperature range of operation, −40°C to 125°C. Specifications appearing in normal type apply for TA = TJ = 25°C. Unless otherwise specified VIN=12V for the 3.3V, 5V and Adjustable versions and VIN=24V for the 12V version. Symbol Parameter Conditions Min Typ Max Units 4.2 6 mA 1.181/1.169 1.21 1.229/1.246 V 5.
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LM2679 www.ti.com SNVS026N – MARCH 2000 – REVISED APRIL 2013 Typical Performance Characteristics Normalized Output Voltage Line Regulation Figure 4. Figure 5. Efficiency vs Input Voltage Efficiency vs ILOAD Figure 6. Figure 7. Switch Current Limit Operating Quiescent Current Figure 8. Figure 9.
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LM2679 SNVS026N – MARCH 2000 – REVISED APRIL 2013 www.ti.com Typical Performance Characteristics (continued) Switching Frequency Feedback Pin Bias Current Figure 10. Figure 11. Continuous Mode Switching Waveforms VIN = 20V, VOUT = 5V, ILOAD = 5A L = 10 μH, COUT = 400 μF, COUTESR = 13 mΩ Discontinuous Mode Switching Waveforms VIN = 20V, VOUT = 5V, ILOAD = 500 mA L = 10 μH, COUT = 400 μF, COUTESR = 13 mΩ A. VSW Pin Voltage, 10 V/div. B. Inductor Current, 2 A/div C.
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LM2679 www.ti.
PAGE 8
LM2679 SNVS026N – MARCH 2000 – REVISED APRIL 2013 www.ti.com APPLICATION HINTS The LM2679 provides all of the active functions required for a step-down (buck) switching regulator. The internal power switch is a DMOS power MOSFET to provide power supply designs with high current capability, up to 5A, and highly efficient operation. The LM2679 is part of the SIMPLE SWITCHER® family of power converters.
PAGE 9
LM2679 www.ti.com SNVS026N – MARCH 2000 – REVISED APRIL 2013 SOFTSTART A capacitor connected from pin 7 to ground allows for a slow turn-on of the switching regulator. The capacitor sets a time delay to gradually increase the duty cycle of the internal power switch. This can significantly reduce the amount of surge current required from the input supply during an abrupt application of the input voltage. If softstart is not required this pin should be left open circuited.
PAGE 10
LM2679 SNVS026N – MARCH 2000 – REVISED APRIL 2013 www.ti.com The individual components from the various manufacturers called out for use are still just a small sample of the vast array of components available in the industry. While these components are recommended, they are not exclusively the only components for use in a design. After a close comparison of component specifications, equivalent devices from other manufacturers could be substituted for use in an application.
PAGE 11
LM2679 www.ti.com SNVS026N – MARCH 2000 – REVISED APRIL 2013 The RMS current and working voltage (WV) ratings of the output capacitor are also important considerations. In a typical step-down switching regulator, the inductor ripple current (set to be no more than 30% of the maximum load current by the inductor selection) is the current that flows through the output capacitor. The capacitor RMS current rating must be greater than this ripple current.
PAGE 12
LM2679 SNVS026N – MARCH 2000 – REVISED APRIL 2013 www.ti.com The peak switch current is equal to a factor of 37,125 divided by RADJ. A resistance of 5.6KΩ sets the current limit to typically 6.3A and an RADJ of 8.25KΩ reduces the maximum current to approximately 4.4A. For predictable control of the current limit it is recommended to keep the peak switch current greater than 3A. For lower current applications a 3A switching regulator with adjustable current limit, the LM2673, is available.
PAGE 13
LM2679 www.ti.com SNVS026N – MARCH 2000 – REVISED APRIL 2013 A simple test to determine if this condition might exist for a suspect application is to apply a short circuit across the output of the converter, and then remove the shorted output condition. In an application with properly selected external components, the output will recover smoothly. Practical values of external components that have been experimentally found to work well under these specific operating conditions are COUT = 47µF, L = 22µH.
PAGE 14
LM2679 SNVS026N – MARCH 2000 – REVISED APRIL 2013 www.ti.com Step 2: Select an LM2679T-3.3. The output voltage will have a tolerance of ±2% at room temperature and ±3% over the full operating temperature range. Step 3: Use the nomograph for the 3.3V device, Figure 18. The intersection of the 16V horizontal line (Vin max) and the 4A vertical line (Iload max) indicates that L46, a 15μH inductor, is required.
PAGE 15
LM2679 www.ti.com SNVS026N – MARCH 2000 – REVISED APRIL 2013 ADJUSTABLE OUTPUT DESIGN EXAMPLE In this example it is desired to convert the voltage from a two battery automotive power supply (voltage range of 20V to 28V, typical in large truck applications) to the 14.8VDC alternator supply typically used to power electronic equipment from single battery 12V vehicle systems. The load current required is 3.5A maximum. It is also desired to implement the power supply with all surface mount components.
PAGE 16
LM2679 SNVS026N – MARCH 2000 – REVISED APRIL 2013 www.ti.com Step 4: Use Table 12 and Table 13 to determine an output capacitor. With a 14.8V output the 12.5 to 15V row is used and with a 47μH inductor there are three surface mount output capacitor solutions. Table 3 and Table 4 provide the actual capacitor characteristics based on the C Code number.
PAGE 17
LM2679 www.ti.com SNVS026N – MARCH 2000 – REVISED APRIL 2013 Inductor Selection Guides For Continuous Mode Operation Figure 18. LM2679-3.3 Figure 19. LM2679-5.0 Figure 20. LM2679-12 Figure 21.
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LM2679 SNVS026N – MARCH 2000 – REVISED APRIL 2013 www.ti.com Table 1. Inductor Manufacturer Part Numbers Inductor Reference Number Inductance (µH) Current (A) L23 33 L24 22 L25 Renco Pulse Engineering Through Hole Surface Mount Coilcraft Through Hole Surface Mount 1.35 RL-5471-7 RL1500-33 PE-53823 PE-53823S DO3316-333 1.65 RL-1283-22-43 RL1500-22 PE-53824 PE-53824S DO3316-223 15 2.00 RL-1283-15-43 RL1500-15 PE-53825 PE-53825S DO3316-153 L29 100 1.
PAGE 19
LM2679 www.ti.com SNVS026N – MARCH 2000 – REVISED APRIL 2013 Capacitor Selection Guides Table 3. Input and Output Capacitor Codes—Surface Mount Capacitor Reference Code Surface Mount AVX TPS Series Sprague 594D Series Kemet T495 Series C (µF) WV (V) Irms (A) C (µF) WV (V) Irms (A) C (µF) WV (V) Irms (A) C1 330 6.3 1.15 120 6.3 1.1 100 6.3 0.82 C2 100 10 1.1 220 6.3 1.4 220 6.3 1.1 C3 220 10 1.15 68 10 1.05 330 6.3 1.1 C4 47 16 0.89 150 10 1.35 100 10 1.
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LM2679 SNVS026N – MARCH 2000 – REVISED APRIL 2013 www.ti.com Table 4. Input and Output Capacitor Codes—Through Hole Through Hole Capacitor Reference Code Sanyo OS-CON SA Series Sanyo MV-GX Series Nichicon PL Series Irms (A) C (µF) WV (V) Irms (A) C (µF) WV (V) 6.3 1 1000 6.3 0.8 680 10 6.3 1.95 270 16 0.6 820 10 330 6.3 2.45 470 16 0.75 1000 10 100 10 1.87 560 16 0.95 1200 10 220 10 2.36 820 16 1.25 2200 C6 33 16 0.96 1000 16 1.3 C7 100 16 1.
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LM2679 www.ti.com SNVS026N – MARCH 2000 – REVISED APRIL 2013 Table 6. Output Capacitors for Fixed Output Voltage Application—Surface Mount (1) (2) Surface Mount Output Voltage (V) Inductance (µH) 3.3 5 12 (1) (2) AVX TPS Series Sprague 594D Series Kemet T495 Series No. C Code No. C Code No.
PAGE 22
LM2679 SNVS026N – MARCH 2000 – REVISED APRIL 2013 www.ti.com Table 8. Input Capacitors for Fixed Output Voltage Application—Surface Mount (1) (2) (3) Surface Mount Output Voltage (V) Inductance (µH) 3.3 5 12 (1) (2) (3) (4) AVX TPS Series Sprague 594D Series Kemet T495 Series No. C Code No. C Code No.
PAGE 23
LM2679 www.ti.com SNVS026N – MARCH 2000 – REVISED APRIL 2013 Table 10. Schottky Diode Selection Table Reverse Voltage (V) Surface Mount 3A 20V SK32 30V SK33 Through Hole 5A or More 3A 5A or More 1N5820 SR302 MBRD835L 1N5821 30WQ03F 40V 31DQ03 SK34 MBRD1545CT 1N5822 1N5825 30BQ040 6TQ045S MBR340 MBR745 30WQ04F 31DQ04 80SQ045 MBRS340 SR403 6TQ045 MBRD340 50V or More SK35 MBR350 30WQ05F 31DQ05 SR305 Table 11.
PAGE 24
LM2679 SNVS026N – MARCH 2000 – REVISED APRIL 2013 www.ti.com Table 12. Output Capacitors for Adjustable Output Voltage Applications—Surface Mount (1) (2) Surface Mount Output Voltage (V) 1.21 to 2.50 2.5 to 3.75 3.75 to 5 5 to 6.25 6.25 to 7.5 7.5 to 10 10 to 12.5 12.5 to 15 15 to 20 20 to 30 30 to 37 (1) (2) (3) 24 Inductance (µH) AVX TPS Series Sprague 594D Series Kemet T495 Series No. C Code No. C Code No.
PAGE 25
LM2679 www.ti.com SNVS026N – MARCH 2000 – REVISED APRIL 2013 Table 13. Output Capacitors for Adjustable Output Voltage Applications—Through Hole (1) (2) Through Hole Output Voltage (V) 1.21 to 2.50 2.5 to 3.75 3.75 to 5 5 to 6.25 6.25 to 7.5 7.5 to 10 10 to 12.5 12.5 to 15 15 to 20 Inductance (µH) Sanyo OS-CON SA Series 30 to 37 (1) (2) (3) Nichicon PL Series Panasonic HFQ Series No. C Code No. C Code No. C Code No.
PAGE 26
LM2679 SNVS026N – MARCH 2000 – REVISED APRIL 2013 www.ti.com REVISION HISTORY Changes from Revision M (April 2013) to Revision N • 26 Page Changed layout of National Data Sheet to TI format ..........................................................................................................
PAGE 27
PACKAGE OPTION ADDENDUM www.ti.com 1-Nov-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (°C) Device Marking (4/5) LM2679S-12/NOPB ACTIVE DDPAK/ TO-263 KTW 7 45 Pb-Free (RoHS Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2679 S-12 LM2679S-3.3 NRND DDPAK/ TO-263 KTW 7 45 TBD Call TI Call TI -40 to 125 LM2679 S-3.3 LM2679S-3.
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PACKAGE OPTION ADDENDUM www.ti.com 1-Nov-2013 Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (°C) Device Marking (4/5) LM2679SX-5.0/NOPB ACTIVE DDPAK/ TO-263 KTW 7 500 Pb-Free (RoHS Exempt) CU SN Level-3-245C-168 HR -40 to 125 LM2679 S-5.
PAGE 29
PACKAGE OPTION ADDENDUM www.ti.com 1-Nov-2013 (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line.
PAGE 30
PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant LM2679SD-12 VSON NHM 14 250 178.0 16.4 5.3 6.3 1.5 12.0 16.0 Q1 LM2679SD-3.3/NOPB VSON NHM 14 250 178.0 16.4 5.3 6.3 1.5 12.0 16.0 Q1 LM2679SD-5.0 VSON NHM 14 250 178.0 16.4 5.3 6.3 1.5 12.0 16.0 Q1 LM2679SD-5.
PAGE 31
PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM2679SD-12 VSON NHM 14 250 210.0 185.0 35.0 LM2679SD-3.3/NOPB VSON NHM 14 250 210.0 185.0 35.0 LM2679SD-5.0 VSON NHM 14 250 210.0 185.0 35.0 LM2679SD-5.0/NOPB VSON NHM 14 250 210.0 185.0 35.0 LM2679SD-ADJ/NOPB VSON NHM 14 250 210.0 185.0 35.0 LM2679SDX-3.3/NOPB VSON NHM 14 2500 367.0 367.
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MECHANICAL DATA NDZ0007B TA07B (Rev E) www.ti.
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MECHANICAL DATA NHM0014A SRC14A (Rev A) www.ti.
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MECHANICAL DATA KTW0007B TS7B (Rev E) BOTTOM SIDE OF PACKAGE www.ti.
PAGE 35
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