SNVSA15B December   2013  – December 2015 LP8557

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Function and Configurations
  7. 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  Boost Converter Electrical Characteristics
    7. 7.7  LED Driver Electrical Characteristics (LED1 To LED6 Pins)
    8. 7.8  PWM Interface Characteristics (PWM Pin)
    9. 7.9  Logic Interface Characteristics (PWM, FSET/SDA, ISET/SCL Pins)
    10. 7.10 I2C Serial Bus Timing Parameters (SDA, SCL)
    11. 7.11 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Boost Converter Overview
        1. 8.3.1.1 Operation
        2. 8.3.1.2 Adaptive Boost Output Voltage Control
      2. 8.3.2 Brightness Control
        1. 8.3.2.1 PWM Input Duty Measurement
        2. 8.3.2.2 BRTMODE = 00b
        3. 8.3.2.3 BRTMODE = 01b
        4. 8.3.2.4 BRTMODE = 10b
        5. 8.3.2.5 BRTMODE = 11b
        6. 8.3.2.6 Hybrid PWM & I Dimming Control
        7. 8.3.2.7 Phase Shift PWM Scheme
      3. 8.3.3 Slope and Advanced Slope
      4. 8.3.4 LED String Count Auto Detection
      5. 8.3.5 EMI Reduction Schemes
      6. 8.3.6 Fault Detection
        1. 8.3.6.1 LED Short Detection
        2. 8.3.6.2 LED OPEN* Detection
        3. 8.3.6.3 Undervoltage Detection
        4. 8.3.6.4 Thermal Shutdown
        5. 8.3.6.5 Boost Overcurrent Protection
        6. 8.3.6.6 Boost Overvoltage Protection
        7. 8.3.6.7 Boost Undervoltage Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Active Mode
    5. 8.5 Programming
      1. 8.5.1 I2C-Compatible Serial Bus Interface
        1. 8.5.1.1 Interface Bus Overview
        2. 8.5.1.2 Start and Stop Conditions
        3. 8.5.1.3 Data Transactions
        4. 8.5.1.4 Acknowledge Cycle
        5. 8.5.1.5 Acknowledge After Every Byte Rule
        6. 8.5.1.6 Control Register Write Cycle
        7. 8.5.1.7 Control Register Read Cycle
        8. 8.5.1.8 Register Read and Write Detail
    6. 8.6 Register Maps
      1. 8.6.1 Register Bit Descriptions
        1. 8.6.1.1  COMMAND
        2. 8.6.1.2  STATUS
        3. 8.6.1.3  BRTLO
        4. 8.6.1.4  BRTHI
        5. 8.6.1.5  CONFIG
        6. 8.6.1.6  CURRENT
        7. 8.6.1.7  PGEN
        8. 8.6.1.8  BOOST
        9. 8.6.1.9  LEDEN
        10. 8.6.1.10 STEP
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Designing With LP8557
        1. 9.1.1.1 Setting Boost Switching and PWM Dimming Frequencies
        2. 9.1.1.2 Setting Boost Compensation
        3. 9.1.1.3 Setting Full-Scale Led Current
      2. 9.1.2 Designing With LP8557I
        1. 9.1.2.1 Setting Boost Switching Frequency
        2. 9.1.2.2 Setting Boost Compensation
        3. 9.1.2.3 Setting PWM Dimming Frequency
        4. 9.1.2.4 Setting Full-Scale LED Current
    2. 9.2 Typical Applications
      1. 9.2.1 LP8557 PWM-Only Option
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Boost Output Capacitor Selection
          2. 9.2.1.2.2 Schottky Diode Selection
          3. 9.2.1.2.3 Inductor Selection
          4. 9.2.1.2.4 Boost Input andVDD Capacitor Selection
        3. 9.2.1.3 Application Curves
      2. 9.2.2 LP8557I PWM and I2C Device Option
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Boost Output Capacitor Placement
      2. 11.1.2 Schottky Diode Placement
      3. 11.1.3 Inductor Placement
      4. 11.1.4 Boost Input and VDD Capacitor Placement
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Related Links
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

5 Device Comparison Table

ORDERABLE DEVICE DEVICE OPTION PACKAGE TOP MARK PACKAGE TYPE (DRAWING) PINS PACKAGE QTY.
LP8557AYFQT "PWM Only" - Recommended for systems without an I2C master D40 DSBGA (YFQ) 16 250
LP8557AYFQR 3000
LP8557IAYFQT "PWM and I2C" - Recommended for systems with an I2C master D41 250
LP8557IAYFQR 3000