SNVSBM6A April   2020  – January 2021 LM5181

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 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Integrated Power MOSFET
      2. 8.3.2  PSR Flyback Modes of Operation
      3. 8.3.3  Setting the Output Voltage
        1. 8.3.3.1 Diode Thermal Compensation
      4. 8.3.4  Control Loop Error Amplifier
      5. 8.3.5  Precision Enable
      6. 8.3.6  Configurable Soft Start
      7. 8.3.7  External Bias Supply
      8. 8.3.8  Minimum On-Time and Off-Time
      9. 8.3.9  Overcurrent Protection
      10. 8.3.10 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Standby Mode
      3. 8.4.3 Active Mode
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Design 1: Wide VIN, Low IQ PSR Flyback Converter Rated at 5 V, 0.5 A
        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  Custom Design With Excel Quickstart Tool
          3. 9.2.1.2.3  Flyback Transformer – T1
          4. 9.2.1.2.4  Flyback Diode – DFLY
          5. 9.2.1.2.5  Zener Clamp Circuit – DF, DCLAMP
          6. 9.2.1.2.6  Output Capacitor – COUT
          7. 9.2.1.2.7  Input Capacitor – CIN
          8. 9.2.1.2.8  Feedback Resistor – RFB
          9. 9.2.1.2.9  Thermal Compensation Resistor – RTC
          10. 9.2.1.2.10 UVLO Resistors – RUV1, RUV2
          11. 9.2.1.2.11 Soft-Start Capacitor – CSS
      2. 9.2.2 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
      2. 12.1.2 Development Support
        1. 12.1.2.1 Custom Design With WEBENCH® Tools
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

Electrical Characteristics

Typical values correspond to TJ = 25°C. Minimum and maximum limits aaply over the full –40°C to 150°C junction temperature range unless otherwise indicated. VIN = 24 V and VEN/UVLO = 2 V unless otherwise stated.
PARAMETERTEST CONDITIONSMINTYPMAXUNIT
SUPPLY CURRENT
ISHUTDOWNVIN shutdown currentVEN/UVLO = 0 V3µA
IACTIVEVIN active currentVEN/UVLO = 2.5 V, VRSET = 1.8 V260350µA
IACTIVE-BIASVIN current with BIAS connectedVSS/BIAS = 6 V2540µA
VSD-FALLINGShutdown thresholdVEN/UVLO falling0.3V
ENABLE AND INPUT UVLO
VSD-RISINGStandby thresholdVEN/UVLO rising0.81V
VUV-RISINGEnable thresholdVEN/UVLO rising1.451.51.53V
VUV-HYSTEnable voltage hysteresisVEN/UVLO falling
 
0.040.05V
IUV-HYSTEnable current hysteresisVEN/UVLO = 1.6 V4.255.5µA
FEEDBACK
IRSETRSET currentRRSET = 12.1 kΩ100µA
VRSETRSET regulation voltageRRSET = 12.1 kΩ1.1911.211.224V
VFB-VIN1FB to VIN voltageIFB = 80 µA–40mV
VFB-VIN2FB to VIN voltageIFB = 120 µA40mV
SWITCHING FREQUENCY
FSW-MINMinimum switching frequency12kHz
FSW-MAXMaximum switching frequency350kHz
tON-MINMinimum switch on-time140ns
DIODE THERMAL COMPENSATION
VTCTC voltageITC = ±10 µA, TJ = 25°C1.21.27V
POWER SWITCHES
RDS(on)MOSFET on-state resistanceISW = 100 mA0.4Ω
SOFT-START AND BIAS
ISSSS ext capacitor charging current5µA
tSSInternal SS time6ms
VBIAS-UVLO-RISEBIAS enable voltageVSS/BIAS rising5.55.75V
VBIAS-UVLO-HYSTBIAS UVLO hysteresisVSS/BIAS falling190mV
CURRENT LIMIT
ISW-PEAKPeak current limit threshold0.620.750.88A
THERMAL SHUTDOWN
TSDThermal shutdown thresholdTJ rising175°C
TSD-HYSThermal shutdown hysteresis6°C