Fairchild Semiconductor
FAN5609
LED Driver with Adaptive Charge Pump DC/DC Converter

General Description

More LED driver product information

The FAN5609 generates regulated output current from a battery with input voltage varying between 2.7V to 5V. Switch reconfiguration and fractional switching techniques are utilized to achieve high efficiency over the entire input voltage range. A proprietary internal circuitry continuously monitors each LED current loop and automatically adjusts the generated output DC voltage to the lowest minimum value required by the LED having the highest forward voltage. This adaptive nature of the FAN5609 eliminates the need for LED pre-selection (matching) and ensures operation at high efficiency. When the input voltage is sufficiently high to sustain the programmed current level in the LEDs, the FAN5609 re-configures itself to operate as a linear regulator, and the DC-DC converter is turned off. An internal two-bit digital to analog converter provides programmability of the output currents. Only two 0.1µF bucket capacitors and two 4.7µF input/output capacitors are needed for proper operation.

Soft-start circuitry prevents excessive current draw during power on. The device has built-in short circuit protection.

Features

  • Parallel LED Driver Supports All Forward Voltages
  • Adaptive VOUT Adjustment to the Highest Diode Voltage
  • Internally Matched LED Current Sources
  • No External Components Needed to Set LED Current
  • Built-in Charge Pump has Three Modes of Operation:
    • Linear Regulation VIN > 4.2V
    • 3/2 DC-DC Converter and Regulation 3.6V < VIN < 4.2V
    • 2/1 DC-DC Converter and Regulation 2.7V < VIN < 3.6V
  • Up to 86% Efficiency
  • Low EMI, Low Ripple
  • Up to 80mA Output Current (4 x 20mA)
  • Built-in DAC for Digital or PWM Brightness Control
  • Can be Duty Cycle Modulated between 0 to 18mA
  • 2.7V to 5.5V Input Voltage Range
  • ICC < 2µA in Shutdown Mode
  • 1MHz Operating Frequency
  • Shutdown Isolates Output from Input
  • Soft-Start Limits Inrush Current
  • Short Circuit Protection
  • Minimal External Components Needed
  • Available in a 14-lead TSSOP Package
  • Available in a 16-lead MLP Package

Applications

  • Cell phones
  • Handheld computers
  • PDA, DSC, MP3 players
  • Keyboard backlight
  • LED displays

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Product Status/Pricing/Packaging      buy now

ProductProduct statusEco StatusPackage typeLeadsPacking methodPackage DrawingPackage Marking Convention**
FAN5609MPXLifetime BuyGreenMLP16TAPE REEL MLP16ALine 1: $Y (Fairchild logo)
&Z (Asm. Plant Code)
&2 (2-Digit Date Code)
&K Line 2: 5609MP Line 3: C

Package marking information for product FAN5609 is available. Click here for more information .


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Product
FAN5609MPX


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