SNVS549C June   2009  – February 2016 LM3554

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 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 Timing Requirements
    7. 5.7 Typical Characteristics
  6. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  Start-Up
      2. 6.3.2  Overvoltage Protection
      3. 6.3.3  Current Limit
      4. 6.3.4  Flash Termination (Strobe-Initiated Flash)
      5. 6.3.5  Flash Termination (I2C-Initiated Flash)
      6. 6.3.6  Flash Timeout
      7. 6.3.7  Torch Mode
      8. 6.3.8  TX1/Torch
      9. 6.3.9  ENVM/TX2/GPIO2
        1. 6.3.9.1 ENVM/TX2/GPIO2/INT as an Interrupt Output
      10. 6.3.10 Indicator LED/Thermistor (LEDI/NTC)
        1. 6.3.10.1 LED Indicator Mode (LEDI)
        2. 6.3.10.2 Thermal Comparator Mode (NTC)
      11. 6.3.11 Alternative External Torch (AET Mode)
      12. 6.3.12 Input Voltage Monitor
      13. 6.3.13 LM3554 Timing Diagrams
      14. 6.3.14 Flags Register and Fault Indicators
      15. 6.3.15 Thermal Shutdown
      16. 6.3.16 LED Fault
      17. 6.3.17 Flash Timeout
      18. 6.3.18 LED Thermal Fault
      19. 6.3.19 Input Voltage Monitor Fault
      20. 6.3.20 TX1 And TX2 Interrupt Flags
      21. 6.3.21 Light Load Disable
    4. 6.4 Device Functional Modes
      1. 6.4.1 Flash Mode
      2. 6.4.2 Pass Mode
      3. 6.4.3 Voltage-Output Mode
    5. 6.5 Programming
      1. 6.5.1 I2C-Compatible Interface
        1. 6.5.1.1 Start and Stop Conditions
        2. 6.5.1.2 I2C-Compatible Chip Address
        3. 6.5.1.3 Transferring Data
    6. 6.6 Register Maps
      1. 6.6.1 Register Descriptions
        1. 6.6.1.1 Torch Brightness Register
        2. 6.6.1.2 Flash Brightness Register
        3. 6.6.1.3 Flash Duration Register
        4. 6.6.1.4 Flags Register
        5. 6.6.1.5 Configuration Register 1
        6. 6.6.1.6 Configuration Register 2
        7. 6.6.1.7 GPIO Register
        8. 6.6.1.8 VIN Monitor Register
  7. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Output Capacitor Selection
        2. 7.2.2.2 Input Capacitor Selection
        3. 7.2.2.3 Inductor Selection
        4. 7.2.2.4 NTC Thermistor Selection
        5. 7.2.2.5 NTC Thermistor Placement
        6. 7.2.2.6 Maximum Load Current (Voltage Mode)
        7. 7.2.2.7 Maximum Output Power
          1. 7.2.2.7.1 Voltage-Output Mode
          2. 7.2.2.7.2 LED Boost Mode
          3. 7.2.2.7.3 LED Pass Mode
      3. 7.2.3 Application Curves
  8. 8 Power Supply Recommendations
  9. 9 Layout
    1. 9.1 Layout Guidelines
    2. 9.2 Layout Example
  10. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Community Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

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

1 Features

  • Input Voltage: 2.5 V to 5.5 V
  • Programmable 4.5-V or 5-V Constant Output Voltage
  • Dual High-Side Current Sources
  • Grounded Cathode Allowing for Better Heat Sinking and LED Routing
  • > 90% Efficiency
  • Ultra-Small Solution Size: < 23 mm2
  • Four Operating Modes: Torch, Flash, LED Indicator, and Voltage Output
  • Accurate and Programmable LED Current from 37.5 mA to 1.2 A
  • Hardware Flash and Torch Enable
  • LED Thermal Sensing and Current Scaleback
  • Software Selectable Input Voltage Monitor
  • Programmable Flash Timeout
  • Dual Synchronization Inputs for RF Power-Amplifier Pulse Events
  • Open and Short LED Detection
  • Active High Hardware Enable for Protection Against System Faults
  • 400-kHz I2C-Compatible Interface

2 Applications

  • Camera Phone LED Flash Controller
  • Class D Audio Amplifier Power
  • LED Current Source Biasing

3 Description

The LM3554 is a 2-MHz fixed-frequency, current-mode synchronous boost converter. The device is designed to operate as a dual 600-mA (1.2 A total) constant-current driver for high-current white LEDs, or as a regulated 4.5-V or 5-V voltage source.

The main features include: an I2C-compatible interface for controlling the LED current or the desired output voltage, a hardware flash enable input for direct triggering of the flash pulse, and dual TX inputs which force the flash pulse into a low-current torch mode allowing for synchronization to RF power amplifier events or other high-current conditions. Additionally, an active high hardware enable (HWEN) input provides a hardware shutdown during system software failures.

Five protection features are available within the LM3554 including a software selectable input voltage monitor, an internal comparator for interfacing with an external temperature sensor, four selectable current limits to ensure the battery current is kept below a predetermined peak level, an overvoltage protection feature to limit the output voltage during LED open circuits, and an output short circuit protection which limits the output current during shorts to GND.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (MAX)
LM3554 DSBGA (16) 1.685 mm × 1.685 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application Circuit

LM3554 typapp_snvs549.gif