SNVS085Y July   2000  – January 2026 LM3478

PRODUCTION DATA  

  1.   1
  2. Features
  3. Applications
  4. Description
  5. Pin Configuration and Functions
  6. Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Overvoltage Protection
      2. 6.3.2 Slope Compensation Ramp
      3. 6.3.3 Frequency Adjust/Shutdown
      4. 6.3.4 Short-Circuit Protection
    4. 6.4 Device Functional Modes
  8. Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Applications
      1. 7.2.1 Typical High Efficiency Step-Up (Boost) Converter
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
          1. 7.2.1.2.1  Custom Design with WEBENCH Tools
          2. 7.2.1.2.2  Power Inductor Selection
          3. 7.2.1.2.3  Programming the Output Voltage
          4. 7.2.1.2.4  Setting the Current Limit
          5. 7.2.1.2.5  Current Limit with External Slope Compensation
          6. 7.2.1.2.6  Power Diode Selection
          7. 7.2.1.2.7  Power MOSFET Selection
          8. 7.2.1.2.8  Input Capacitor Selection
          9. 7.2.1.2.9  Output Capacitor Selection
          10. 7.2.1.2.10 Compensation
        3. 7.2.1.3 Application Curves
      2. 7.2.2 Typical SEPIC Converter
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
          1. 7.2.2.2.1 Power MOSFET Selection
          2. 7.2.2.2.2 Power Diode Selection
          3. 7.2.2.2.3 Selection of Inductors L1 and L2
          4. 7.2.2.2.4 Sense Resistor Selection
          5. 7.2.2.2.5 Sepic Capacitor Selection
          6. 7.2.2.2.6 Input Capacitor Selection
          7. 7.2.2.2.7 Output Capacitor Selection
        3. 7.2.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. Device and Documentation Support
    1. 8.1 Third-Party Products Disclaimer
    2. 8.2 Custom Design with WEBENCH Tools
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Documentation Support
      1. 8.4.1 Related Documentation
    5. 8.5 Support Resources
    6. 8.6 Trademarks
    7. 8.7 Electrostatic Discharge Caution
    8. 8.8 Glossary
  10. Revision History
  11. 10Mechanical, Packaging, and Orderable Information

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订购信息

Typical Characteristics

Unless otherwise specified, VIN = 12V, TJ = 25°C.

LM3478 IQ vs Input
                        Voltage (Shutdown)Figure 5-1 IQ vs Input Voltage (Shutdown)
LM3478 ISupply vs
                            VIN (Switching)Figure 5-3 ISupply vs VIN (Switching)
LM3478 Frequency vs
                        TemperatureFigure 5-5 Frequency vs Temperature
LM3478 Current Sense Threshold vs
                        Input VoltageFigure 5-7 Current Sense Threshold vs Input Voltage
LM3478 Efficiency vs Load Current
                        (3.3V Input and 12V Output)Figure 5-9 Efficiency vs Load Current (3.3V Input and 12V Output)
LM3478 Efficiency vs Load Current
                        (9V Input and 12V Output)Figure 5-11 Efficiency vs Load Current (9V Input and 12V Output)
LM3478 Error Amplifier
                        GainFigure 5-13 Error Amplifier Gain
LM3478 COMP Pin Source Current vs
                        TemperatureFigure 5-15 COMP Pin Source Current vs Temperature
LM3478 Compensation Ramp vs
                        Compensation ResistorFigure 5-17 Compensation Ramp vs Compensation Resistor
LM3478 Duty Cycle vs Current
                        Sense VoltageFigure 5-19 Duty Cycle vs Current Sense Voltage
LM3478 ISupply vs
                        Input Voltage (Non-Switching)
Figure 5-2 ISupply vs Input Voltage (Non-Switching)
LM3478 Switching Frequency vs
                            RFAFigure 5-4 Switching Frequency vs RFA
LM3478 Drive Voltage vs Input
                        VoltageFigure 5-6 Drive Voltage vs Input Voltage
LM3478 COMP Pin Voltage vs Load
                        CurrentFigure 5-8 COMP Pin Voltage vs Load Current
LM3478 Efficiency vs Load Current
                        (5V Input and 12V Output)Figure 5-10 Efficiency vs Load Current (5V Input and 12V Output)
LM3478 Efficiency vs Load Current
                        (3.3V Input and 5V Output)Figure 5-12 Efficiency vs Load Current (3.3V Input and 5V Output)
LM3478 Error Amplifier
                        PhaseFigure 5-14 Error Amplifier Phase
LM3478 Short Circuit Sense
                        Voltage vs Input VoltageFigure 5-16 Short Circuit Sense Voltage vs Input Voltage
LM3478 Shutdown Threshold
                        Hysteresis vs TemperatureFigure 5-18 Shutdown Threshold Hysteresis vs Temperature