SNVS569C May   2009  – October 2016 LM3550

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Timing Requirements
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 STROBE Pin
      2. 7.3.2 End-of-Charge Pin (EOC)
      3. 7.3.3 ALD/TEMP Pin
      4. 7.3.4 IND Pin
      5. 7.3.5 BAL Pin
      6. 7.3.6 Super-Capacitor Charging Time
      7. 7.3.7 Super-Capacitor Voltage Profile
      8. 7.3.8 Peak Flash Current
      9. 7.3.9 Maximum Flash Duration
    4. 7.4 Device Functional Modes
      1. 7.4.1 State Machine Description
        1. 7.4.1.1 Basic Description
        2. 7.4.1.2 Shutdown State
        3. 7.4.1.3 Torch State
        4. 7.4.1.4 Charge State
          1. 7.4.1.4.1 Fixed-Voltage-Charge Mode
          2. 7.4.1.4.2 Optimal Charge Mode
        5. 7.4.1.5 Torch and Charge State
        6. 7.4.1.6 Flash State
        7. 7.4.1.7 EOC Functionality
        8. 7.4.1.8 State Diagram FGATE = 1
        9. 7.4.1.9 Optimal Charge Mode vs Fixed Voltage Mode
          1. 7.4.1.9.1 Optimal Charge Mode vs Fixed Voltage Mode
    5. 7.5 Programming
      1. 7.5.1 I2C-Compatible Interface
        1. 7.5.1.1 Data Validity
        2. 7.5.1.2 Start and Stop Conditions
        3. 7.5.1.3 Transferring Data
        4. 7.5.1.4 I2C-Compatible Child Address: 0x53
    6. 7.6 Register Maps
      1. 7.6.1 Internal Registers
        1. 7.6.1.1 General Purpose Register Description
        2. 7.6.1.2 Current Control Register Description
        3. 7.6.1.3 Options Control Register Description
        4. 7.6.1.4 ALD/TEMP Sense High/Low Registers
  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 Super-Capacitor
          2. 8.2.2.1.2 Boost Capacitors
          3. 8.2.2.1.3 Current Source FET
          4. 8.2.2.1.4 ALD/TEMP Components
            1. 8.2.2.1.4.1 NTC Selection
            2. 8.2.2.1.4.2 Ambient Light Sensor
          5. 8.2.2.1.5 Thermal Protection
      3. 8.2.3 Application 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 Device Nomenclature
    2. 11.2 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

5 Pin Configuration and Functions

NHU Package
16-Pin UQFN
Top View
LM3550 pinout_top_view_snvs569.gif
NHU Package
16-Pin UQFN
Bottom View
LM3550 pinout_bottom_view_snvs569.gif

Pin Functions

PIN TYPE DESCRIPTION
NAME NUMBER
ALD/TEMP 12 Input Ambient light sensor or temperature monitoring pin. For ambient light sensing, connect a light sensor or photo-diode and a resistor to this pin. For temperature monitoring, connect a NTC thermistor from VCC to the NTC pin and a resistor from the NTC pin to ground.
BAL 2 Power Super-capacitor active balance pin
C1+ 20 Power Flying capacitor pins. Connect a 1-µF ceramic capacitor from C1+ to C1− and C2+ to C2−.
C1– 18
C2+ 15
C2– 16
EOC 6 Output End-of-charge output/ flash ready. The EOC pin transitions from high to low when an end of charge flash ready. The EOC pin transitions from high to low when an end of charge state has been reached
FB 5 Input Programmable feedback voltage pin
FET_CON 4 Output External FET controller. Connect gate of flash NFET to this pin.
IND 13 Output Indicator LED current source. Drives one red LED with a 5-mA current
LED- 3 Input Regulated current sink input for torch mode
SCL 10 Input I2C serial clock pin
SDA 8 Input/Output I2C serial data I/O pin
STROBE 11 Input Manual flash enable pin. The STROBE pin can be configured to be rising-edge sensitive with the flash timing controlled internally, or level sensitive with the flash timing being controlled externally.
VIN 14 Input Input voltage connection. A 1-μF ceramic capacitor is required from VIN to GND.
VOUT 1 Output Charge pump output. A 1-μF ceramic capacitor is required from VOUT to GND. Connect the flash LED anodes and super-capacitor to this pin.
GND 7,9,17,19, DAP Ground Ground pins – these pins should be connected directly to a low-impedance ground plane.