SNAS744B July   2017  – March 2018 LMS3655

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Circuit
      2.      LMS3655 Efficiency: VOUT = 5 V
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Thermal Information (for Device Mounted on PCB)
    6. 7.6 Electrical Characteristics
    7. 7.7 System Characteristics
    8. 7.8 Timing Requirements
    9. 7.9 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
      1. 8.2.1 Control Scheme
    3. 8.3 Feature Description
      1. 8.3.1 RESET Flag Output
      2. 8.3.2 Enable and Start-Up
      3. 8.3.3 Soft-Start Function
      4. 8.3.4 Current Limit
      5. 8.3.5 Hiccup Mode
      6. 8.3.6 Synchronizing Input
      7. 8.3.7 Undervoltage Lockout (UVLO) and Thermal Shutdown (TSD)
      8. 8.3.8 Input Supply Current
    4. 8.4 Device Functional Modes
      1. 8.4.1 AUTO Mode
      2. 8.4.2 FPWM Mode
      3. 8.4.3 Dropout
      4. 8.4.4 Spread-Spectrum Operation
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 General Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 External Components Selection
            1. 9.2.1.2.1.1 Input Capacitors
            2. 9.2.1.2.1.2 Output Inductors and Capacitors
              1. 9.2.1.2.1.2.1 Inductor Selection
              2. 9.2.1.2.1.2.2 Output Capacitor Selection
          2. 9.2.1.2.2 FB for Adjustable Output
          3. 9.2.1.2.3 VCC
          4. 9.2.1.2.4 BIAS
          5. 9.2.1.2.5 CBOOT
          6. 9.2.1.2.6 Maximum Ambient Temperature
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Adjustable 5-V Output
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
      3. 9.2.3 Adjustable 3.3-V Output
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedure
        3. 9.2.3.3 Application Curves
      4. 9.2.4 6-V Adjustable Output
        1. 9.2.4.1 Design Requirements
        2. 9.2.4.2 Detailed Design Procedure
        3. 9.2.4.3 Application Curves
    3. 9.3 Do's and Don't's
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.7 System Characteristics

The following specifications are ensured by design provided that the component values in the typical application circuit are used. These parameters are not ensured by production testing. Limits apply over the recommended operating junction temperature range of –40°C to +150°C, unless otherwise noted. Minimum and maximum limits are specified through test, design, or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only. Unless otherwise stated the following conditions apply: VIN = 13.5 V.
PARAMETERTEST CONDITIONSMINTYPMAXUNIT
VIN-MIN Minimum input voltage for full functionality at 3.5-A load, after start-up. VOUT = 3.3 V +2% or –3% regulation 3.5 V
Minimum input voltage for full functionality at maximum rated load 5.5 A after start-up. VOUT = 3.3 V +2% or –3% regulation 3.8
VOUT Output voltage VIN = VOUT + 1 V to 36 V, IOUT = 3.5 A –2.25% 2.25%
FSW Switching frequency VIN = 24 V, FPWM = 24V, VOUT = 3.3 V, IOUT = 200 mA 400 kHz
IQ_VIN Input current to VIN pin VIN = 13.5 V, VOUT = 3.3 V, IOUT = 0 A , FPWM = 0, RFBT = 49.9 kΩ, RFBB = 21.7 kΩ 32 µA
VIN = 13.5 V, VOUT = 5.0 V, IOUT = 0 A, FPWM = 0, RFBT = 49.9 kΩ, RFBB = 12.4 kΩ 57
IB Bias current in AUTO mode at no load VIN = 13.5 V, IOUT = 0 A, FPWM = 0 32 42 µA
VDROP1 Minimum input to output voltage differential to maintain regulation accuracy without inductor DCR drop VOUT = 3.3 V or 5 V, IOUT= 3.5 A, +2% or –3% output accuracy 0.35 0.6 V
VOUT = 3.3 V or 5 V, IOUT= 5.5 A, +2% or –3% output accuracy 0.65 0.85 V
VDROP2 Minimum input to output voltage differential to maintain FSW ≥ 330 kHz without inductor DCR drop VOUT = 3.3 V or 5 V, IOUT = 3.5 A,
FSW = 330 kHz, 2% regulation accuracy		 0.5 0.7 V
VOUT = 3.3 V or 5 V, IOUT = 5.5 A,
FSW = 330 kHz, 2% regulation accuracy		 0.7 1.2 V
Efficiency Typical efficiency VIN = 13.5 V, VOUT = 5 V, IOUT = 3.5 A 94%
VIN = 13.5 V, VOUT = 3.3 V, IOUT = 3.5 A 92%
VIN = 13.5 V, VOUT = 5 V, IOUT = 100 mA 92%