SNVS124F November   1999  – April 2021 LM2596

PRODUCTION DATA  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Description (continued)
  6. Pin Configuration and Functions
  7. Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Electrical Characteristics – 3.3-V Version
    6. 7.6  Electrical Characteristics – 5-V Version
    7. 7.7  Electrical Characteristics – 12-V Version
    8. 7.8  Electrical Characteristics – Adjustable Voltage Version
    9. 7.9  Electrical Characteristics – All Output Voltage Versions
    10. 7.10 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Delayed Start-Up
      2. 8.3.2 Undervoltage Lockout
      3. 8.3.3 Inverting Regulator
      4. 8.3.4 Inverting Regulator Shutdown Methods
    4. 8.4 Device Functional Modes
      1. 8.4.1 Discontinuous Mode Operation
  9. Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Input Capacitor (CIN)
      2. 9.1.2 Feedforward Capacitor (CFF)
      3. 9.1.3 Output Capacitor (COUT)
      4. 9.1.4 Catch Diode
      5. 9.1.5 Inductor Selection
      6. 9.1.6 Output Voltage Ripple and Transients
      7. 9.1.7 Open-Core Inductors
    2. 9.2 Typical Applications
      1. 9.2.1 LM2596 Fixed Output Series Buck Regulator
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Custom Design with WEBENCH Tools
          2. 9.2.1.2.2 Inductor Selection (L1)
          3. 9.2.1.2.3 Output Capacitor Selection (COUT)
          4. 9.2.1.2.4 Catch Diode Selection (D1)
          5. 9.2.1.2.5 Input Capacitor (CIN)
        3. 9.2.1.3 Application Curves
      2. 9.2.2 LM2596 Adjustable Output Series Buck Regulator
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
          1. 9.2.2.2.1 Programming Output Voltage
          2. 9.2.2.2.2 Inductor Selection (L1)
          3. 9.2.2.2.3 Output Capacitor Selection (COUT)
          4. 9.2.2.2.4 Feedforward Capacitor (CFF)
          5. 9.2.2.2.5 Catch Diode Selection (D1)
          6. 9.2.2.2.6 Input Capacitor (CIN)
        3. 9.2.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
    3. 11.3 Thermal Considerations
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
      2. 12.1.2 Custom Design with WEBENCH Tools
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • NDH|5
  • NEB|5
  • KTT|5
Thermal pad, mechanical data (Package|Pins)
Orderable Information
Catch Diode Selection (D1)
  1. The catch diode current rating must be at least 1.3 times greater than the maximum load current. Also, if the power supply design must withstand a continuous output short, the diode must have a current rating equal to the maximum current limit of the LM2596. The most stressful condition for this diode is an overload or shorted output condition. See Table 9-4. In this example, a 5-A, 20-V, 1N5823 Schottky diode will provide the best performance, and will not be overstressed even for a shorted output.
    Table 9-4 Diode Selection Table
    VR3-A DIODES4-A TO 6-A DIODES
    SURFACE-MOUNTTHROUGH-HOLESURFACE-MOUNTTHROUGH-HOLE
    SCHOTTKYULTRA FAST RECOVERYSCHOTTKYULTRA FAST RECOVERYSCHOTTKYULTRA FAST RECOVERYSCHOTTKYULTRA FAST RECOVERY
    20 VAll of
    these
    diodes
    are
    rated to
    at least
    50V.
    1N5820All of
    these
    diodes
    are
    rated to
    at least
    50V.
    All of
    these
    diodes
    are
    rated to
    at least
    50V.
    SR502All of
    these
    diodes
    are
    rated to
    at least
    50V.
    SK32SR3021N5823
    MBR320SB520
    30 V30WQ031N5821
    SK33MBR33050WQ03SR503
    31DQ031N5824
    1N5822SB530
    40 VSK34SR30450WQ04SR504
    MBRS340MBR3401N5825
    30WQ04MURS32031DQ04MUR320MURS620SB540MUR620
    50 VSK3530WF10SR30550WF10HER601
    orMBRS360MBR35050WQ05SB550
    More30WQ0531DQ0550SQ080
  2. The reverse voltage rating of the diode must be at least 1.25 times the maximum input voltage.
  3. This diode must be fast (short reverse recovery time) and must be placed close to the LM2596 using short leads and short-printed circuit traces. Because of their fast switching speed and low forward voltage drop, Schottky diodes provide the best performance and efficiency, and must be the first choice, especially in low output voltage applications. Ultra-fast recovery, or high-efficiency rectifiers also provide good results. Ultra-fast recovery diodes typically have reverse recovery times of 50 ns or less. Rectifiers such as the 1N5400 series must not be used because they are too slow.