SLUS774C AUGUST   2007  – December 2014

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3  Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Voltage Reference
      2. 7.3.2  Oscillator
      3. 7.3.3  Input Undervoltage Lockout (UVLO) and Startup
      4. 7.3.4  Enable and Timed Turn On of the Outputs
      5. 7.3.5  Output Voltage Sequencing
      6. 7.3.6  Soft-Start
      7. 7.3.7  Output Voltage Regulation
      8. 7.3.8  Feedback Loop and Inductor-Capacitor (L-C) Filter Selection
      9. 7.3.9  Inductor-Capacitor (L-C) Selection
      10. 7.3.10 Maximum Output Capacitance
      11. 7.3.11 Minimum Output Capacitance
      12. 7.3.12 Modifying The Feedback Loop
        1. 7.3.12.1 Using High-ESR Output Capacitors
        2. 7.3.12.2 Using All Ceramic Output Capacitors
      13. 7.3.13 Example: TPS54386 Buck Converter Operating at 12-V Input, 3.3-V Output and 400-mA(P-P) Ripple Current
      14. 7.3.14 Bootstrap for the N-Channel MOSFET
      15. 7.3.15 Light Load Operation
      16. 7.3.16 SW Node Ringing
        1. 7.3.16.1 SW Node Snubber
        2. 7.3.16.2 Bootstrap Resistor
      17. 7.3.17 Output Overload Protection
      18. 7.3.18 Operating Near Maximum Duty Cycle
      19. 7.3.19 Dual Supply Operation
      20. 7.3.20 Cascading Supply Operation
      21. 7.3.21 Multiphase Operation
      22. 7.3.22 Bypass and FIltering
      23. 7.3.23 Overtemperature Protection and Junction Temperature Rise
      24. 7.3.24 Power Derating
    4. 7.4 Device Functional Modes
      1. 7.4.1 Minimum Input Voltage
      2. 7.4.2 ENx Control
  8. 8 Applications and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 12-V to 5-V and 3.3-V Converter
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1  Duty Cycle Estimation
          2. 8.2.1.2.2  Inductor Selection
          3. 8.2.1.2.3  Rectifier Diode Selection
          4. 8.2.1.2.4  Output Capacitor Selection
          5. 8.2.1.2.5  Voltage Setting
          6. 8.2.1.2.6  Compensation Capacitors
          7. 8.2.1.2.7  Input Capacitor Selection
          8. 8.2.1.2.8  Boot Strap Capacitor
          9. 8.2.1.2.9  ILIM
          10. 8.2.1.2.10 SEQ
          11. 8.2.1.2.11 Power Dissipation
        3. 8.2.1.3 Application Curves
      2. 8.2.2 24-V to 12-V and 24-V to 5-V
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
      3. 8.2.3 5-V to 3.3V and 5-V to 1.2 V
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
        3. 8.2.3.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 PowerPAD Package
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Definition of Symbols
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Related Links
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

11 Device and Documentation Support

11.1 Device Support

The following parts have characteristics similar to the TPS54383/6 and may be of interest.

Table 4. Devices Related to the TPS54383 and TPS54386

TI LITERATURE NUMBER DEVICE DESCRIPTION
SLUS642 TPS40222 5-V Input, 1.6-A Non-Synchronous Buck Converter
SLUS749 TPS54283 / TPS54286 2-A Dual Non-Synchronous Converter with Integrated High-Side MOSFET

11.1.1 Definition of Symbols

CDJ Average junction capacitance of the rectifier diode from 0V to VIN(max)
COSS Average output capacitance of the switching MOSFET from 0V to VIN(max)
COUT Output Capacitor
D(max) Maximum steady state operating duty cycle
D(min) Minimum steady state operating duty cycle
ESR(max) Maximum allowable output capacitor ESR
fSW Switching frequency
IBP Output Current of BP regulator due to external loads
IDD Switching quiescent current with no load on BP
ID(avg) Average diode conduction current
ID(peak) Peak diode conduction current
IIN(avg) Average input current
IIN(rms) Root mean squared (RMS) input current
IL(avg) Average inductor current
IL(rms) Root mean squared (RMS) inductor current
IL(peak) Peak current in inductor
ILRIP(max) Maximum allowable inductor ripple current
L(min) Minimum inductor value to maintain desired ripple current
IOUT(max) Maximum designed output current
IRMS(cin) Root mean squared (RMS) current through the input capacitor
IRIPPLE Inductor peak to peak ripple current
IQSW(rms) Root mean squared current through the switching MOSFET
PCON Power loss due to conduction through switching MOSFET
PD(max) Maximum power dissipation in diode
RDS(on) Drain to source resistance of the switching MOSFET when “ON”
PSW Power loss due to switching
PREG Power loss due to the internal regulator
VBP Output Voltage of BP regulator
V(BR)R(min) Minimum reverse breakdown voltage rating for rectifier diode
VFB Regulated feedback voltage
VFD Forward voltage drop across rectifier diode
VIN Power stage input voltage
VOUT Regulated output voltage
VRIPPLE(cap) Peak-to-Peak ripple voltage due to ideal capacitor (ESR = 0)
VRIPPLE(tot) Maximum allowable peak-to-peak output ripple voltage

11.2 Documentation Support

11.2.1 Related Documentation

These references, design tools and links to additional references, including design software, may be found at http:www.power.ti.com

  • PowerPAD Thermally Enhanced Package Application Report, SLMA002
  • PowerPAD™ Made Easy, SLMA004
  • Under The Hood Of Low Voltage DC/DC Converters. SEM1500 Topic 5, 2002 Seminar Series, SLUP206
  • Understanding Buck Power Stages in Switchmode Power Supplies, SLVA057
  • Designing Stable Control Loops. SEM 1400, 2001 Seminar Series, SLUP173

11.3 Related Links

The table below lists quick access links. Categories include technical documents, support and community resources, tools and software, and quick access to sample or buy.

Table 5. Related Links

PARTS PRODUCT FOLDER SAMPLE & BUY TECHNICAL DOCUMENTS TOOLS & SOFTWARE SUPPORT & COMMUNITY
TPS54383 Click here Click here Click here Click here Click here
TPS54386 Click here Click here Click here Click here Click here

11.4 Trademarks

PowerPAD is a trademark of Texas Instruments.

All other trademarks are the property of their respective owners.

11.5 Electrostatic Discharge Caution

esds-image

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.

11.6 Glossary

SLYZ022 — TI Glossary.

This glossary lists and explains terms, acronyms, and definitions.