SNVSBJ3A April   2020  – September 2020 LM25183

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  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 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  Integrated Power MOSFET
      2. 7.3.2  PSR Flyback Modes of Operation
      3. 7.3.3  Setting the Output Voltage
        1. 7.3.3.1 Diode Thermal Compensation
      4. 7.3.4  Control Loop Error Amplifier
      5. 7.3.5  Precision Enable
      6. 7.3.6  Configurable Soft Start
      7. 7.3.7  External Bias Supply
      8. 7.3.8  Minimum On-Time and Off-Time
      9. 7.3.9  Overcurrent Protection
      10. 7.3.10 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Standby Mode
      3. 7.4.3 Active Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Design 1: Wide VIN, Low IQ PSR Flyback Converter Rated at 12 V, 0.6 A
        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  Custom Design With Excel Quickstart Tool
          3. 8.2.1.2.3  Flyback Transformer – T1
          4. 8.2.1.2.4  Flyback Diode – DFLY
          5. 8.2.1.2.5  Leakgae Inductance Clamp Circuit – DF, DCLAMP
          6. 8.2.1.2.6  Output Capacitor – COUT
          7. 8.2.1.2.7  Input Capacitor – CIN
          8. 8.2.1.2.8  Feedback Resistor – RFB
          9. 8.2.1.2.9  Thermal Compensation Resistor – RTC
          10. 8.2.1.2.10 UVLO Resistors – RUV1, RUV2
          11. 8.2.1.2.11 Soft-Start Capacitor – CSS
          12.        50
      2. 8.2.2 Application Curves
      3. 8.2.3 Design 2: PSR Flyback Converter With Dual Outputs of 15 V and –15 V at 0.3 A
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
          1. 8.2.3.2.1 Flyback Transformer – T1
          2. 8.2.3.2.2 Flyback Diodes – DFLY1 and DFLY2
          3. 8.2.3.2.3 Input Capacitor – CIN
          4. 8.2.3.2.4 Output Capacitors – COUT1, COUT2
          5. 8.2.3.2.5 Feedback Resistor – RFB
          6. 8.2.3.2.6 Thermal Compensation Resistor – RTC
          7. 8.2.3.2.7 Output Voltage Clamp Zeners – DOUT1 and DOUT2
        3. 8.2.3.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  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 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.3.1 Design Requirements

The required input, output, and performance parameters for this application example are shown in Table 8-4.

Table 8-4 Design Parameters
DESIGN PARAMETER VALUE
Input voltage range (steady state) 4.5 V to 42 V
Output 1 voltage and current (at VIN ≥ 24 V) 15 V, 0.3 A
Output 2 voltage and current (at VIN ≥ 24 V) –15 V, 0.3 A
Input UVLO thresholds 4.5 V on, 4 V off
Output voltage regulation ±2%

The target full-load efficiency of this LM25183 design is 90% based on a nominal input voltage of 24 V and isolated output voltages of 15 V and –15 V sharing a common return. The selected flyback converter components are cited in Table 8-5, including the following:

  • A multi-winding flyback transformer
  • Input and output capacitors
  • Flyback rectifying diodes
  • A flyback converter IC
Table 8-5 List of Components for Design 2
REF DES QTY SPECIFICATION VENDOR PART NUMBER
CIN 1 10 µF, 50 V, X7R, 1210, ceramic TDK C3225X7R1H106M250AC
Taiyo Yuden UMK325AB7106KM-T
COUT1, COUT2 4 22 µF, 25 V, X7R, 1210, ceramic TDK C3225X7R1E226M250AB
Taiyo Yuden TMK325B7226MM-PR
DCLAMP 1 Zener, 20 V, 3 W, SMA 3SMAJ5932B Micro Commercial
DF 1 Schottky diode, 60 V, 3 A, SOD-123FL FSV360FP OnSemi
DFLY1, DFLY2 2 Schottky diode, 100 V, 1 A, POWERDI123 DFLS1100-7 Diodes Inc.
DOUT1, DOUT2 2 Zener, 18 V, 5%, SOD-523 BZX585-C18 Nexperia
RFB 1 102 kΩ, 1%, 0402 Std Std
RSET 1 12.1 kΩ, 1%, 0402 Std Std
RTC 1 221 kΩ, 1%, 0402 Std Std
T1 1 9 µH, 3 A, 1 : 1.5 : 1.5, 13 mm × 11 mm × 10 mm Coilcraft ZB1056-AE
U1 1 LM25183 PSR flyback converter, VSON-8 Texas Instruments LM25183NGUR