SNAS714B November   2016  – March 2018 LMS3635-Q1 , LMS3655-Q1

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      LMS3655-Q1 Conducted EMI: VOUT = 5 V, IOUT = 5 A
      2.      LMS3655-Q1 Efficiency: VOUT = 5 V
  4. Revision History
  5. Device Comparison Tables
  6. Pin Configuration and Functions
    1.     Pin Functions
  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. 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. 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 Setting the Output Voltage
          3. 9.2.1.2.3 FB for Adjustable Output
          4. 9.2.1.2.4 VCC
          5. 9.2.1.2.5 BIAS
          6. 9.2.1.2.6 CBOOT
          7. 9.2.1.2.7 Maximum Ambient Temperature
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Fixed 5-V Output for USB-Type Applications
        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 Fixed 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 Related Links
    4. 12.4 Receiving Notification of Documentation Updates
    5. 12.5 Community Resources
    6. 12.6 Trademarks
    7. 12.7 Electrostatic Discharge Caution
    8. 12.8 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

Timing Requirements

Limits apply over the recommended operating junction temperature range of –40°C to +150°C, unless otherwise noted. Minimum and maximum limits are ensured 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.
MIN NOM MAX UNIT
tON Minimum switch on-time, VIN = 18 V, IL = 1 A 60 84 ns
tOFF Minimum switch off-time, VIN = 3.8 V, IL = 1 A 65 80 ns
tRESET-act Delay time to RESET high signal 2 3 4 ms
tRESET-filter Glitch filter time for RESET function(1) 24 µs
tSS Soft-start time from first switching pulse to VREF at 90% 2.5 4 5 ms
tEN Turnon delay, CVCC = 4.7 µF(2) 0.8 ms
tW Short-circuit wait time (hiccup time)(3) 6 ms
tFPWM Change transition time from AUTO to FPWM MODE, 10-mA load, VIN = 13.5 V 250 µs
Change transition time from FPWM to AUTO MODE, 10-mA load, VIN = 13.5 V 450
This is the time from the rising edge of EN to the time that the soft-start ramp begins.
Tw is the wait time between current limit trip and restart. Tw is proportional to the soft-start time. However, provision must be made to make Tw longer to ensure survivability during an output short circuit.