SNVSA03E October   2014  – October 2018 LM5160 , LM5160A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Synchronous Buck Application Circuit
      2.      Typical Fly-Buck Application Circuit
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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 Switching Characteristics
    7. 6.7 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  Control Circuit
      2. 7.3.2  VCC Regulator
      3. 7.3.3  Regulation Comparator
      4. 7.3.4  Soft Start
      5. 7.3.5  Error Amplifier
      6. 7.3.6  On-Time Generator
      7. 7.3.7  Current Limit
      8. 7.3.8  N-Channel Buck Switch and Driver
      9. 7.3.9  Synchronous Rectifier
      10. 7.3.10 Enable / Undervoltage Lockout (EN/UVLO)
      11. 7.3.11 Thermal Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Forced Pulse Width Modulation (FPWM) Mode
      2. 7.4.2 Undervoltage Detector
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Ripple Configuration
    2. 8.2 Typical Applications
      1. 8.2.1 LM5160 Synchronous Buck (10-V to 60-V Input, 5-V Output, 1.5-A Load)
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1  Custom Design With WEBENCH® Tools
          2. 8.2.1.2.2  Feedback Resistor Divider - RFB1, RFB2
          3. 8.2.1.2.3  Switching Frequency - RON
          4. 8.2.1.2.4  Inductor - L
          5. 8.2.1.2.5  Output Capacitor - COUT
          6. 8.2.1.2.6  Series Ripple Resistor - RESR
          7. 8.2.1.2.7  VCC and Bootstrap Capacitors - CVCC, CBST
          8. 8.2.1.2.8  Input Capacitor - CIN
          9. 8.2.1.2.9  Soft-Start Capacitor - CSS
          10. 8.2.1.2.10 EN/UVLO Resistors - RUV1, RUV2
        3. 8.2.1.3 Application Curves
      2. 8.2.2 LM5160 Isolated Fly-Buck (18-V to 32-V Input, 12-V, 4.5-W Isolated Output)
        1. 8.2.2.1 LM5160 Fly-Buck Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1 Selection of VOUT1 and Turns Ratio
          2. 8.2.2.2.2 Secondary Rectifier Diode
          3. 8.2.2.2.3 External Ripple Circuit
          4. 8.2.2.2.4 Output Capacitor - COUT2
        3. 8.2.2.3 Application Curves
      3. 8.2.3 LM5160A Isolated Fly-Buck (18-V to 32-V Input, 12-V, 4.5-W Isolated Output)
    3. 8.3 Do's and Don'ts
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
      2. 11.1.2 Development Support
        1. 11.1.2.1 Custom Design With WEBENCH® Tools
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Related Links
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Community Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

10.1 Layout Guidelines

A proper layout is essential for optimum performance of the circuit. In particular, observe the following guidelines:

  • CIN: The loop consisting of input capacitor (CIN), VIN pin and PGND pin carries the switching current. The input capacitor must be placed close to the IC, directly across VIN and PGND pins, and the connections to these two pins must be direct to minimize the switching power loop area. In general, it is not possible to place all of input capacitances near the IC. A good layout practice includes placing the bulk capacitor(s) as close as possible to the VIN pin (see Figure 36).
  • CVCC and CBST: The VCC and bootstrap (BST) bypass capacitors supply switching currents to the high-side and low-side gate drivers. These two capacitors must also be placed as close to the IC as possible, and the connecting trace length and loop area must be minimized (see Figure 36).
  • The feedback trace carries the output voltage information and a small ripple component that is necessary for proper operation of the LM5160/A. Therefore, take care while routing the feedback trace to avoid coupling any noise into this pin. In particular, the feedback trace must be short and not run close to magnetic components, or parallel to any other switching trace.
  • SW trace: The SW node switches rapidly between VIN and GND every cycle and is therefore a source of noise. The SW node copper area must be minimized. In particular, the SW node must not be inadvertently connected to a copper plane or pour.