SNVSAJ8D February   2016  – March 2018 LM36273

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     Simplified Schematic
  3. 3 Description
    1.     Backlight Efficiency, 3P7S
  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 I2C Timing Requirements (Fast Mode)
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Features Description
      1. 7.3.1 Enabling the LM36273
      2. 7.3.2 Backlight
        1. 7.3.2.1 Current Sink Enable
        2. 7.3.2.2 Brightness Mapping
          1. 7.3.2.2.1 Linear Mapping
          2. 7.3.2.2.2 Exponential Mapping
        3. 7.3.2.3 Backlight Brightness Control Modes
          1. 7.3.2.3.1 I2C Brightness Control (PWM Pin Disabled)
          2. 7.3.2.3.2 I2C × PWM Brightness Control (PWM Pin Enabled)
            1. 7.3.2.3.2.1 PWM Ramper
        4. 7.3.2.4 Boost Switching Frequency
          1. 7.3.2.4.1 Minimum Inductor Select
        5. 7.3.2.5 Boost Feedback Gain Select
        6. 7.3.2.6 Auto Switching Frequency
        7. 7.3.2.7 PWM Input
          1. 7.3.2.7.1 PWM Sample Frequency
            1. 7.3.2.7.1.1 PWM Resolution and Input Frequency Range
            2. 7.3.2.7.1.2 PWM Sample Rate and Efficiency
              1. 7.3.2.7.1.2.1 PWM Sample Rate Example
          2. 7.3.2.7.2 PWM Hysteresis
          3. 7.3.2.7.3 PWM Step Response
          4. 7.3.2.7.4 PWM Timeout
          5. 7.3.2.7.5 PWM-to-Digital Code Readback
        8. 7.3.2.8 Regulated Headroom Voltage
        9. 7.3.2.9 Backlight Fault Protection and Faults
          1. 7.3.2.9.1 Backlight Overvoltage Protection (OVP)
          2. 7.3.2.9.2 Backlight Overcurrent Protection (OCP)
      3. 7.3.3 LCM Bias
        1. 7.3.3.1 Display Bias Boost Converter (VVPOS, VVNEG)
        2. 7.3.3.2 Auto Sequence Mode
        3. 7.3.3.3 Wake-up Mode
          1. 7.3.3.3.1 Wake1 Mode
          2. 7.3.3.3.2 Wake2 Mode
        4. 7.3.3.4 Active Discharge
        5. 7.3.3.5 LCM Bias Protection and Faults
          1. 7.3.3.5.1 LCM Overvoltage (OVP) Protection
          2. 7.3.3.5.2 VPOS Short-Circuit Protection
          3. 7.3.3.5.3 VNEG Short-Circuit Protection
      4. 7.3.4 Software Reset
      5. 7.3.5 HWEN Input
      6. 7.3.6 Thermal Shutdown (TSD)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Modes of Operation
    5. 7.5 Programming
      1. 7.5.1 I2C-Compatible Serial Bus Interface
        1. 7.5.1.1 Interface Bus Overview
        2. 7.5.1.2 Data Transactions
        3. 7.5.1.3 Acknowledge Cycle
        4. 7.5.1.4 Acknowledge After Every Byte Rule
        5. 7.5.1.5 Addressing Transfer Formats
        6. 7.5.1.6 Register Programming
    6. 7.6 Register Maps
      1. 7.6.1  Revision Register (Address = 0x01)[Reset = 0x01]
        1. Table 11. Revision Register Field Descriptions
      2. 7.6.2  Backlight Configuration1 Register (Address = 0x02)[Reset = 0x28]
        1. Table 12. Backlight Configuration 1 Register Field Descriptions
      3. 7.6.3  Backlight Configuration 2 Register (Address = 0x03)[Reset = 0x8D]
        1. Table 13. Backlight Configuration 2 Register Field Descriptions
      4. 7.6.4  Backlight Brightness LSB Register (Address = 0x04)[Reset = 0x07]
        1. Table 14. Backlight Brightness LSB Register Field Descriptions
      5. 7.6.5  Backlight Brightness MSB Register (Address = 0x05)[Reset = 0xFF]
        1. Table 15. Backlight Brightness MSB Register Field Descriptions
      6. 7.6.6  Backlight Auto-Frequency Low Threshold Register (Address = 0x06)[Reset = 0x00]
        1. Table 16. Backlight Auto-Frequency Low Threshold Field Descriptions
      7. 7.6.7  Backlight Auto-Frequency High Threshold Register (Address = 0x07)[Reset = 0x00]
        1. Table 17. Backlight Auto-Frequency High Threshold Field Descriptions
      8. 7.6.8  Backlight Enable Register (Address = 0x08)[Reset = 0x00]
        1. Table 18. Backlight Enable Register Field Descriptions
      9. 7.6.9  Bias Configuration 1 Register (Address = 0x09)[Reset = 0x18]
        1. Table 19. Bias Configuration 1 Register Field Descriptions
      10. 7.6.10 Bias Configuration 2 register (Address = 0x0A)[Reset = 0x11]
        1. Table 20. Bias Configuration 2 Register Field Descriptions
      11. 7.6.11 Bias Configuration 3 Register (Address = 0x0B)[Reset = 0x00]
        1. Table 21. Bias Configuration 3 Register Field Descriptions
      12. 7.6.12 LCM Boost Bias Register (Address = 0x0C)[Reset = 0x28]
        1. Table 22. LCM Boost Bias Register Field Descriptions
      13. 7.6.13 VPOS Bias Register (Address = 0x0D)[Reset = 0x1E]
        1. Table 23. VPOS Bias Register Field Descriptions
      14. 7.6.14 VNEG Bias Register (Address = 0x0E)[Reset = 0x1C]
        1. Table 24. VNEG Bias Register Field Descriptions
      15. 7.6.15 Flags Register (Address = 0x0F)[Reset = 0x00]
        1. Table 25. Flags Register Field Descriptions
      16. 7.6.16 Option 1 Register (Address = 0x10)[Reset = 0x06]
        1. Table 26. Option 1 Register Field Descriptions
      17. 7.6.17 Option 2 Register (Address = 0x11)[Reset = 0x35]
        1. Table 27. Option 2 Register Field Descriptions
      18. 7.6.18 PWM-to-Digital Code Readback LSB Register (Address = 0x12)[Reset = 0x00]
        1. Table 28. PWM-to-Digital Code Readback LSB Register Field Descriptions
      19. 7.6.19 PWM-to-Digital Code Readback MSB Register (Address = 0x13)[Reset = 0x00]
        1. Table 29. PWM-to-Digital Code Readback MSB Register Field Descriptions
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Component Selection
          1. 8.2.2.1.1 Inductor Selection
          2. 8.2.2.1.2 Boost Output Capacitor Selection
          3. 8.2.2.1.3 Input Capacitor Selection
      3. 8.2.3 Application Curves
        1. 8.2.3.1 Backlight Curves
          1. 8.2.3.1.1 Two LED Strings
          2. 8.2.3.1.2 Three LED Strings
        2. 8.2.3.2 LCM Bias Curves
  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
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community 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

10.1 Layout Guidelines

  • Place the boost converter output capacitors as close to the output voltage and GND pins as possible.
  • Minimize the boost converter switching loops by placing the input capacitors and inductors close to GND and switch pins.
  • If possible, route the switching loops on top layer only. For best efficiency, try to minimize copper on the switch node to minimize switch pin parasitic capacitance while preserving adequate routing width.
  • VIN input voltage pin must be bypassed to ground with a low-ESR bypass capacitor. Place the capacitor as close as possible to VIN pin.
  • Place the output capacitor of the LDO as close to the output pins as possible. Also place the charge pump flying capacitor and output capacitor close to their respective pins.
  • Route the internal pins on the second layer. Use offset micro vias to go from top layer to mid-layer1. Avoid routing the signal traces directly under the switching loops of the boost converters.