3-Channel Constant-Current RGB LED Driver with
Individual PWM Dimming

Description
The CAT4109 is a 3−channel constant−current LED driver,
requiring no inductor. LED channel currents up to 175 mA are
programmed independently via separate external resistors. Low output
voltage operation of 0.4 V at 175 mA allows for more power efficient
designs across wider supply voltage range. The three LED pins are
compatible with high voltage up to 25 V supporting applications with
long strings of LEDs.
Three independent control inputs PWM1, PWM2, PWM3, control
respectively LED1, LED2, LED3 channels. The device also includes
an output enable (OE) control pin to disable all three channels
independently of the PWMx input states.
Thermal shutdown protection is incorporated in the device to
disable the LED outputs whenever the die temperature exceeds 150°C.
The device is available in a 16−lead SOIC package.

Features
• 3 Independent Current Sinks up to 175 mA rated 25 V
• LED Current Set by External Low Power Control Resistors
• Individual PWM Control per Channel
• Low Dropout Current Source (0.4 V at 175 mA)
• Output Enable Input for Dimming
• “Zero” Current Shutdown Mode
• 3 V to 5.5 V Logic Supply
• Thermal Shutdown Protection
• 16−lead SOIC Package
• These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS
Compliant
Application
• Multi−color LED, Architectural Lighting
• LED Signs and Displays
• LCD Backlight