Texas Instruments LM2734 Manual

Texas Instruments LM2734 Manual

Thin sot 1a load step-down dc-dc regulator

Advertisement

Quick Links

www.ti.com
LM2734 Thin SOT 1A Load Step-Down DC-DC Regulator
FEATURES
1
• Thin SOT-6 Package
234
3.0V to 20V Input Voltage Range
0.8V to 18V Output Voltage Range
1A Output Current
550kHz (LM2734Y) and 1.6MHz (LM2734X)
Switching Frequencies
300mΩ NMOS Switch
30nA Shutdown Current
0.8V, 2% Internal Voltage Reference
Internal Soft-Start
Current-Mode, PWM Operation
®
WEBENCH
Online Design Tool
Thermal Shutdown
LM2734XQ/LM2734YQ are AEC-Q100 Grade 1
Qualified and are Manufactured on an
Automotive Grade Flow
APPLICATIONS
Local Point of Load Regulation
Core Power in HDDs
Set-Top Boxes
Battery Powered Devices
USB Powered Devices
DSL Modems
Notebook Computers
Automotive
1
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.
WEBENCH is a registered trademark of Texas Instruments, Inc..
2
WEBENCH is a registered trademark of Texas Instruments.
3
All other trademarks are the property of their respective owners.
4
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.
Check for Samples:
LM2734
DESCRIPTION
The LM2734 regulator is a monolithic, high frequency,
PWM step-down DC/DC converter in a 6-pin Thin
SOT package. It provides all the active functions to
provide local DC/DC conversion with fast transient
response and accurate regulation in the smallest
possible PCB area.
With a minimum of external components and online
design support through WEBENCH
easy to use. The ability to drive 1A loads with an
internal 300mΩ NMOS switch using state-of-the-art
0.5µm BiCMOS technology results in the best power
density available. The world class control circuitry
allows for on-times as low as 13ns, thus supporting
exceptionally high frequency conversion over the
entire 3V to 20V input operating range down to the
minimum output voltage of 0.8V. Switching frequency
is internally set to 550kHz (LM2734Y) or 1.6MHz
(LM2734X), allowing the use of extremely small
surface mount inductors and chip capacitors. Even
though the operating frequencies are very high,
efficiencies up to 90% are easy to achieve. External
shutdown is included, featuring an ultra-low stand-by
current of 30nA. The LM2734 utilizes current-mode
control and internal compensation to provide high-
performance regulation over a wide range of
operating conditions. Additional features include
internal soft-start circuitry to reduce inrush current,
pulse-by-pulse current limit, thermal shutdown, and
output over-voltage protection.
SNVS288I – SEPTEMBER 2004 – REVISED APRIIL 2013
®
, the LM2734 is
Copyright © 2004–2013, Texas Instruments Incorporated
LM2734

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the LM2734 and is the answer not in the manual?

Questions and answers

Summary of Contents for Texas Instruments LM2734

  • Page 1 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. WEBENCH is a registered trademark of Texas Instruments, Inc..
  • Page 2: Typical Application Circuit

    These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 3: Operating Ratings

    For specific specifications and the test conditions, see Electrical Characteristics. (2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and specifications.
  • Page 4: Electrical Characteristics

    EN_TH Enable Threshold Voltage Rising Enable Pin Current Sink/Source Switch Leakage (1) Specified to Average Outgoing Quality Level (AOQL). (2) Typicals represent the most likely parametric norm. Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 5: Typical Performance Characteristics

    = 3.3V Figure 7. Figure 8. Efficiency vs Load Current - "X" V = 1.5V Efficiency vs Load Current - "Y" V = 1.5V Figure 9. Figure 10. Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 6 Figure 12. Current Limit vs Temperature Current Limit vs Temperature = 5V = 20V Figure 13. Figure 14. vs Temperature vs Temperature DSON Figure 15. Figure 16. Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 7 Line Regulation - "X" = 1.5V, I = 500mA = 3.3V, I = 500mA Figure 19. Figure 20. Line Regulation - "Y" = 3.3V, I = 500mA Figure 21. Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 8: Block Diagram

    Output Driver BOOST Lockout Switch Control Current Logic Limit Comparator Oscillator Reset Pulse 0.88V Comparator SENSE Internal Compensation Error Signal Corrective Ramp Error Amplifier 0.8V Figure 22. Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 9: Theory Of Operation

    APPLICATION INFORMATION THEORY OF OPERATION The LM2734 is a constant frequency PWM buck regulator IC that delivers a 1A load current. The regulator has a preset switching frequency of either 550kHz (LM2734Y) or 1.6MHz (LM2734X). These high frequencies allow the LM2734 to operate with small surface mount capacitors and inductors, resulting in DC/DC converters that require a minimum amount of board space.
  • Page 10 BOOST Figure 24. V Charges C BOOST When the LM2734 starts up, internal circuitry from the BOOST pin supplies a maximum of 20mA to C . This BOOST current charges C to a voltage sufficient to turn the switch on. The BOOST pin will continue to source...
  • Page 11 R3 = (10V - 5V) / (1.4 x 2.5mA + 1mA) = 1.11kΩ (11) BOOST V BOOST LM2734 BOOST Figure 26. Boost Voltage Supplied from the Shunt Zener on V Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 12 ENABLE PIN / SHUTDOWN MODE The LM2734 has a shutdown mode that is controlled by the enable pin (EN). When a logic low voltage is applied to EN, the part is in shutdown mode and its quiescent current drops to typically 30nA. Switch leakage adds another 40nA from the input supply.
  • Page 13 A large leaded capacitor will have high ESL and a 0805 ceramic chip capacitor will have very low ESL. At the operating frequencies of the LM2734, certain capacitors may have an ESL so large that the resulting impedance (2πfL) will be higher than that required to Submit Documentation Feedback Copyright ©...
  • Page 14 90° phase shifted from the switching action. Given the availability and quality of MLCCs and the expected output voltage of designs using the LM2734, there is really no need to review any other capacitor technologies. Another benefit of ceramic capacitors is their ability to bypass high frequency noise.
  • Page 15: Pcb Layout Considerations

    The remaining components should also be placed as close as possible to the IC. Please see Application Note AN-1229 SNVA054 for further considerations and the LM2734 demo board as an example of a four-layer layout. LM2734X Circuit Examples BOOST LM2734 Figure 27.
  • Page 16 SS1P3L Vishay D2, Boost Diode @ 50mA Diode 1N4148W Diodes, Inc. 4.7µH, 1.7A VLCF4020T- 4R7N1R2 31.6kΩ, 1% CRCW06033162F Vishay 10kΩ, 1% CRCW06031002F Vishay 100kΩ, 1% CRCW06031003F Vishay Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 17 D3, Zener Diode 5.1V 250Mw SOT BZX84C5V1 Vishay 6.8µH, 1.6A, SLF7032T-6R8M1R6 8.87kΩ, 1% CRCW06038871F Vishay 10.2kΩ, 1% CRCW06031022F Vishay 100kΩ, 1% CRCW06031003F Vishay 4.12kΩ, 1% CRCW06034121F Vishay Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 18 1N4148W Diodes, Inc. D3, Zener Diode 11V 350Mw SOT BZX84C11T Diodes, Inc. 6.8µH, 1.6A, SLF7032T-6R8M1R6 8.87kΩ, 1% CRCW06038871F Vishay 10.2kΩ, 1% CRCW06031022F Vishay 100kΩ, 1% CRCW06031003F Vishay Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 19 1N4148W Diodes, Inc. D3, Zener Diode 4.3V 350mw SOT BZX84C4V3 Diodes, Inc. 6.8µH, 1.6A, SLF7032T-6R8M1R6 102kΩ, 1% CRCW06031023F Vishay 10.2kΩ, 1% CRCW06031022F Vishay 100kΩ, 1% CRCW06031003F Vishay Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 20: Lm2734Y Circuit Examples

    MBRM110L ON Semi D2, Boost Diode @ 50mA Diode 1N4148W Diodes, Inc. 10µH, 1.6A, SLF7032T-100M1R4 8.87kΩ, 1% CRCW06038871F Vishay 10.2kΩ, 1% CRCW06031022F Vishay 100kΩ, 1% CRCW06031003F Vishay Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 21 SS1P3L Vishay D2, Boost Diode 0.6V @ 30mA Diode BAT17 Vishay 10µH, 1.6A, SLF7032T-100M1R4 31.6kΩ, 1% CRCW06033162F Vishay 10.0 kΩ, 1% CRCW06031002F Vishay 100kΩ, 1% CRCW06031003F Vishay Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 22 D3, Zener Diode 5.1V 250Mw SOT BZX84C5V1 Vishay 15µH, 1.5A SLF7045T-150M1R5 8.87kΩ, 1% CRCW06038871F Vishay 10.2kΩ, 1% CRCW06031022F Vishay 100kΩ, 1% CRCW06031003F Vishay 4.12kΩ, 1% CRCW06034121F Vishay Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 23 1N4148W Diodes, Inc. D3, Zener Diode 11V 350Mw SOT BZX84C11T Diodes, Inc. 15µH, 1.5A, SLF7045T-150M1R5 8.87kΩ, 1% CRCW06038871F Vishay 10.2kΩ, 1% CRCW06031022F Vishay 100kΩ, 1% CRCW06031003F Vishay Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 24 1N4148W Diodes, Inc. D3, Zener Diode 4.3V 350mw SOT BZX84C4V3 Diodes, Inc. 22µH, 1.4A, SLF7045T-220M1R3-1PF 102kΩ, 1% CRCW06031023F Vishay 10.2kΩ, 1% CRCW06031022F Vishay 100kΩ, 1% CRCW06031003F Vishay Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 25: Revision History

    SNVS288I – SEPTEMBER 2004 – REVISED APRIIL 2013 REVISION HISTORY Changes from Revision H (April 2013) to Revision I Page • Changed layout of National Data Sheet to TI format ......................Submit Documentation Feedback Copyright © 2004–2013, Texas Instruments Incorporated Product Folder Links: LM2734...
  • Page 26 PACKAGE OPTION ADDENDUM www.ti.com 1-Nov-2013 PACKAGING INFORMATION Orderable Device Status Package Type Package Pins Package Eco Plan Lead/Ball Finish MSL Peak Temp Op Temp (°C) Device Marking Samples Drawing (4/5) LM2734XMK/NOPB ACTIVE 1000 Green (RoHS CU SN Level-1-260C-UNLIM -40 to 125 SFDB &...
  • Page 27 In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. OTHER QUALIFIED VERSIONS OF LM2734, LM2734-Q1 : •...
  • Page 28: Tape And Reel Information

    PACKAGE MATERIALS INFORMATION www.ti.com 8-Apr-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Reel Reel Pin1 Type Drawing Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant (mm) W1 (mm) LM2734XMK/NOPB 1000 178.0 LM2734XMKX/NOPB 3000 178.0 LM2734XQMK/NOPB 1000 178.0 LM2734XQMKE/NOPB...
  • Page 29 PACKAGE MATERIALS INFORMATION www.ti.com 8-Apr-2013 *All dimensions are nominal Device Package Type Package Drawing Pins Length (mm) Width (mm) Height (mm) LM2734XMK/NOPB 1000 210.0 185.0 35.0 LM2734XMKX/NOPB 3000 210.0 185.0 35.0 LM2734XQMK/NOPB 1000 210.0 185.0 35.0 LM2734XQMKE/NOPB 210.0 185.0 35.0 LM2734XQMKX/NOPB 3000 210.0...
  • Page 32: Important Notice

    IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue.

Table of Contents