The LT3909HDD#PBF is a step up LED driver in 12 pin DFN package. This device integrates a constant frequency, current mode boost converter capable of driving up to 36V of LEDs with two high side current sources. Each LED string contains an accurate high side current source with ±1.8% current matching. Output voltage adapts to variations in LED VF for optimum efficiency. Maximum LED current can be programmed from 10mA to 50mA per string using a single resistor. The LED brightness can be reduced with analogue dimming (up to 10:1) or with PWM dimming (up to 40000:1 at 100Hz, up to 160:1 at 25KHz) independent of leakage at VOUT. The LED pins can be paralleled for higher LED current. The LT3909 includes programmable maximum VOUT for open LED protection, fault flag to indicate open LED or LED short to GND and internal regulation loop to safely limit junction temperature. The device also includes internal compensation, internal soft start and micropower shutdown functions.
- 2 string x 50mA LED driver
- Output voltage of 36V
- Wide input voltage range from 2.9V to 40V
- Integrated schottky diode
- Internal 400mohm, 40V and 1A switch
- LED current can be regulated even for VIN > VOUT
- Programmable maximum regulated VOUT
- Accurate EN/UVLO threshold
- Fixed 2MHz switching frequency
- Operating junction temperature range from -40°C to 150°C
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