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LM22676-ADJ

VIN

BOOT

GND

VIN

VOUT

LM22676

LM22676-Q1

www.ti.com

SNVS587K –SEPTEMBER 2008–REVISED APRIL 2013

LM22676/LM22676-Q1 42V, 3A SIMPLE SWITCHER® Step-Down Voltage Regulator with

Features

Check for Samples: LM22676, LM22676-Q1

FEATURES

DESCRIPTION

The LM22676 switching regulator provides all of the

• Wide Input Voltage Range: 4.5V to 42V

functions necessary to implement an efficient high

• Internally Compensated Voltage Mode Control

voltage step-down (buck) regulator using a minimum

• Stable with Low ESR Ceramic Capacitors

of external components. This easy to use regulator

incorporates a 42V N-channel MOSFET switch

• 120 mΩ N-Channel MOSFET PFM Package

capable of providing up to 3A of load current.

• 100 mΩ N-Channel MOSFET PSOP-8 Package

Excellent line and load regulation along with high

• Output Voltage Options:

efficiency (>90%) are featured. Voltage mode control

offers short minimum on-time, allowing the widest

– ADJ (Outputs as Low as 1.285V)

ratio between input and output voltages. Internal loop

– 5.0 (Output Fixed to 5V)

compensation means that the user is free from the

• ±1.5% Feedback Reference Accuracy

tedious task of calculating the loop compensation

components. Fixed 5V output and adjustable output

• Switching Frequency of 500 kHz

voltage options are available. A switching frequency

• -40°C to 125°C Operating Junction

of 500 kHz allows for small external components and

Temperature Range

good transient response. A precision enable input

• Precision Enable Pin

allows simplification of regulator control and system

power sequencing. In shutdown mode the regulator

• Integrated Boot-Strap Diode

draws only 25 µA (typ.). Built in soft-start (500µs, typ)

• Integrated Soft-Start

saves external components. The LM22676 also has

• Fully WEBENCH

Enabled

built in thermal shutdown, and current limiting to

• LM22676Q is an Automotive Grade Product

protect against accidental overloads.

that is AEC-Q100 Grade 1 Qualified (-40°C to

The LM22676 is a member of Texas Instruments'

+125°C Operating Junction Temperature)

SIMPLE SWITCHER™ family. The SIMPLE

SWITCHER™ concept provides for an easy to use

PACKAGE

complete design using a minimum number of external

components and the TI WEBENCH

design tool. TI's

• SO PowerPAD (Exposed Pad

WEBENCH

tool includes features such as external

• PFM (Exposed Pad)

component calculation, electrical simulation, thermal

simulation, and Build-It boards for easy design-in.

APPLICATIONS

Simplified Application Schematic

• Industrial Control

• Telecom and Datacom Systems

• Embedded Systems

• Conversions from Standard 24V, 12V and 5V

Input Rails

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.

2All trademarks are the property of their respective owners.

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 (27 pages)

PAGE 1
LM22676 LM22676-Q1 www.ti.com SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 LM22676/LM22676-Q1 42V, 3A SIMPLE SWITCHER® Step-Down Voltage Regulator with Features Check for Samples: LM22676, LM22676-Q1 FEATURES DESCRIPTION • • • • • • The LM22676 switching regulator provides all of the functions necessary to implement an efficient high voltage step-down (buck) regulator using a minimum of external components.
PAGE 2
LM22676 LM22676-Q1 SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 www.ti.com Connection Diagram BOOT 1 8 SW NC 2 7 VIN NC 3 6 GND FB 4 5 EN Exposed Pad Connect to GND Figure 1. 8-Lead Plastic SO PowerPAD Package Package Number DDA0008B 7 EN 6 FB 5 NC 4 GND 3 BOOT 2 VIN 1 SW Exposed Pad Connect to GND Figure 2.
PAGE 3
LM22676 LM22676-Q1 www.ti.com SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 Absolute Maximum Ratings (1) (2) VIN to GND 43V EN Pin Voltage -0.5V to 6V SW to GND (3) -5V to VIN BOOT Pin Voltage VSW + 7V FB Pin Voltage -0.5V to 7V Power Dissipation Internally Limited Junction Temperature 150°C For soldering specifications, refer to the following document: www.ti.
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LM22676 LM22676-Q1 SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 www.ti.com Electrical Characteristics (continued) Limits in standard type are for TJ = 25°C only; limits in boldface type apply over the junction temperature (TJ) range of -40°C to +125°C. Minimum and Maximum limits are ensured through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TA = TJ = 25°C, and are provided for reference purposes only. Unless otherwise specified: VIN = 12V.
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LM22676 LM22676-Q1 www.ti.com SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 Typical Performance Characteristics Unless otherwise specified the following conditions apply: Vin = 12V, TJ = 25°C. Efficiency vs IOUT and VIN VOUT = 3.3V Normalized Switching Frequency vs Temperature Figure 3. Figure 4. Current Limit vs Temperature Normalized RDS(ON) vs Temperature Figure 5. Figure 6. Feedback Bias Current vs Temperature Normalized Enable Threshold Voltage vs Temperature Figure 7. Figure 8.
PAGE 6
LM22676 LM22676-Q1 SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 www.ti.com Typical Performance Characteristics (continued) Unless otherwise specified the following conditions apply: Vin = 12V, TJ = 25°C. Standby Quiescent Current vs Input Voltage Normalized Feedback Voltage vs Temperature Figure 9. Figure 10. Normalized Feedback Voltage vs Input Voltage Figure 11.
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LM22676 LM22676-Q1 www.ti.com SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 SIMPLIFIED BLOCK DIAGRAM VIN VIN Vcc BOOT INT REG, EN,UVLO EN ILimit PWM Cmp. FB + TYPE III COMP + - LOGIC Error Amp. VOUT SW OSC 1.285V & Soft-start GND Figure 12. Simplified Block Diagram Detailed Operating Description The LM22676 incorporates a voltage mode constant frequency PWM architecture. In addition, input voltage feedforward is used to stabilize the loop gain against variations in input voltage.
PAGE 8
LM22676 LM22676-Q1 SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 www.ti.com Although an internal pull-up is provided on the EN pin, it is good practice to pull the input high, when this feature is not used, especially in noisy environments. This can most easily be done by connecting a resistor between VIN and the EN pin. The resistor is required, since the internal zener diode, at the EN pin, will conduct for voltages above about 6V. The current in this zener must be limited to less than 100 µA.
PAGE 9
LM22676 LM22676-Q1 www.ti.com SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 The second limitation is the maximum duty cycle before the output voltage will "dropout" of regulation. The following equation can be used to approximate the minimum input voltage before dropout occurs: where • The values of TOFF and RDS(ON) are found in the Electrical Characteristics table. (4) The worst case here occurs at the highest load. In this equation, RL is the D.C. inductor resistance.
PAGE 10
LM22676 LM22676-Q1 SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 www.ti.com 45 INPUT VOLTAGE (v) 40 35 30 25 SAFE OPERATING AREA 20 15 10 5 0.0 0.2 0.4 0.6 0.8 1.0 SHORT CIRCUIT VOLTAGE (v) 1.2 Figure 14. SOA Soft-Start The soft-start feature allows the regulator to gradually reach steady-state operation, thus reducing start-up stresses. The internal soft-start feature brings the output voltage up in about 500 µs. This time is fixed and can not be changed.
PAGE 11
LM22676 LM22676-Q1 www.ti.com SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 (9) The Q factor depends on the parasitic resistance of the power stage components and is not typically in the control of the designer. Of course, loop compensation is only one consideration when selecting power stage components; see the Application Information section for more details. COMPENSATOR GAIN (dB) 40 -ADJ -5.0 35 30 25 20 15 10 5 0 100 1k 10k 100k 1M FREQUENCY (Hz) 10M Figure 15.
PAGE 12
LM22676 LM22676-Q1 SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 www.ti.com INDUCTOR The inductor value is determined based on the load current, ripple current, and the minimum and maximum input voltages. To keep the application in continuous conduction mode (CCM), the maximum ripple current, IRIPPLE , should be less than twice the minimum load current.
PAGE 13
LM22676 LM22676-Q1 www.ti.com SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 It is good practice to include a high frequency bypass capacitor as close as possible to the LM22676. This small case size, low ESR, ceramic capacitor should be connected directly to the VIN and GND pins with the shortest possible PCB traces. Values in the range of 0.47 µF to 1 µF are appropriate. This capacitor helps to provide a low impedance supply to sensitive internal circuitry.
PAGE 14
LM22676 LM22676-Q1 SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 www.ti.com Vout RFBT FB RFBB Figure 17. Resistive Feedback Divider A maximum value of 10 kΩ is recommended for the sum of RFBB and RFBT to maintain good output voltage accuracy for the -ADJ option. A maximum of 2 kΩ is recommended for the -5.0 option. For the -5.0 option, the total internal divider resistance is typically 9.93 kΩ.
PAGE 15
LM22676 LM22676-Q1 www.ti.com SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 Figure 18. Current Flow in a Buck Application Thermal Considerations The components with the highest power dissipation are the power diode and the power MOSFET internal to the LM22676 regulator. The easiest method to determine the power dissipation within the LM22676 is to measure the total conversion losses then subtract the power losses in the diode and inductor.
PAGE 16
LM22676 LM22676-Q1 SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 www.ti.
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LM22676 LM22676-Q1 www.ti.com SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 RFBB 2.55 k: VIN 5.5V to 35V VIN FB LM22676-ADJ EN BOOT C2 22 PF + C1 2.2 PF C6 4.7 PF VOUT C3 10 nF L1 10 PH RFBT 7.32 k: SW GND D1 60V 5A C4 120 PF VOUT -5V Figure 19.
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LM22676 LM22676-Q1 SNVS587K – SEPTEMBER 2008 – REVISED APRIL 2013 www.ti.com REVISION HISTORY Changes from Revision J (April 2013) to Revision K • 18 Page Changed layout of National Data Sheet to TI format ..........................................................................................................
PAGE 19
PACKAGE OPTION ADDENDUM www.ti.com 21-May-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish (2) MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) LM22676MR-5.0/NOPB ACTIVE SO PowerPAD DDA 8 95 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 125 L22676 5.0 LM22676MR-ADJ/NOPB ACTIVE SO PowerPAD DDA 8 95 Green (RoHS & no Sb/Br) CU SN Level-3-260C-168 HR -40 to 125 L22676 ADJ LM22676MRE-5.
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PACKAGE OPTION ADDENDUM www.ti.com Orderable Device 21-May-2013 Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish (2) MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) LM22676TJ-ADJ/NOPB ACTIVE TO-263 NDR 7 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LM22676 TJ-ADJ LM22676TJE-5.0/NOPB ACTIVE TO-263 NDR 7 250 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LM22676 TJ-5.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 29-May-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 LM22676MRE-5.0/NOPB SO Power PAD DDA 8 250 178.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LM22676MRE-ADJ/NOPB SO Power PAD DDA 8 250 178.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LM22676MRX-5.0/NOPB SO Power PAD DDA 8 2500 330.0 12.4 6.5 5.4 2.
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PACKAGE MATERIALS INFORMATION www.ti.com 29-May-2013 Device Package Package Pins Type Drawing B Power PAD LM22676QTJ-5.0/NOPB SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant TO-263 NDR 7 1000 330.0 24.4 10.6 15.4 2.45 12.0 24.0 Q2 LM22676QTJ-ADJ/NOPB TO-263 NDR 7 1000 330.0 24.4 10.6 15.4 2.45 12.0 24.0 Q2 LM22676QTJE-5.0/NOPB TO-263 NDR 7 250 178.0 24.4 10.6 15.4 2.45 12.0 24.
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PACKAGE MATERIALS INFORMATION www.ti.com 29-May-2013 Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM22676QMRX-5.0/NOPB SO PowerPAD DDA 8 2500 367.0 367.0 35.0 LM22676QMRX-ADJ/NOP B SO PowerPAD DDA 8 2500 367.0 367.0 35.0 LM22676QTJ-5.0/NOPB TO-263 NDR 7 1000 367.0 367.0 35.0 LM22676QTJ-ADJ/NOPB TO-263 NDR 7 1000 367.0 367.0 35.0 LM22676QTJE-5.0/NOPB TO-263 NDR 7 250 210.0 185.0 35.
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MECHANICAL DATA NDR0007A BOTTOM SIDE OF PACKAGE TOP SIDE OF PACKAGE TJ7A (Rev D) www.ti.
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MECHANICAL DATA DDA0008B MRA08B (Rev B) www.ti.
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