LT3475IFE#PBF

LT®3475 is a dual step-down DC/DC converter designed to operate as a constant-current source. An internal sense resistor monitors the output current allowing accurate current regulation ideal for driving high current LEDs. The high side current sense allows grounded cathode LED operation. High output current accuracy is maintained over a wide current range, from 50mA to 1.5A, allowing a wide dimming range. Unique PWM circuitry allows a dimming range of 3000:1, avoiding the colour shift normally associated with LED current dimming. The high switching frequency offers several advantages, permitting the use of small inductors and ceramic capacitors. The constant switching frequency combined with low-impedance ceramic capacitors result in low, predictable output ripple. Frequency foldback and thermal shutdown provide additional protection. Typical applications are automotive and avionic lighting, architectural detail lighting, display backlighting, constant-current sources.

• True colour PWM™ delivers constant colour with 3000:1 dimming range
• High side current sense allows grounded cathode LED operation
• Anti-phase switching reduces ripple, uses small inductors and ceramic capacitors
• Minimum input voltage is 3.7V typ (TA=25°C. VIN=12V, VBOOST=16V, VOUT=4V)
• Shutdown current is 2μA max (SHDN=0.3V, VBOOST=VOUT=0V)
• Switching frequency range from 530 to 640KHz (RT=24.3k, TA=25°C. VIN=12V, VBOOST=16V, VOUT=4V)
• Maximum duty cycle is 95% (RT=24.3k, TA=25°C. VIN=12V, VBOOST=16V, VOUT=4V)
• 20-lead plastic TSSOP package
• Temperature rating range from –40°C to 125°C

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ADI products are only authorized (and sold) for use by the customer and are not to be resold or otherwise passed on to any third party