LT3950EMSE#PBF

LT®3950 is a multitopology DC/DC converter designed specifically to drive high current LEDs. It contains a 1.5A, 60V DMOS switch and supports an external PWM dimming PMOS. The LT3950 has an internal PWM generator for dimming that maps an analogue control signal to an exponential scale used to define PWM dimming duty ratio. Using an exponential scale to define duty ratio preserves dimming resolution across a wide range of LED current. In addition to operating as a constant current source, the LT3950 also provides output voltage regulation. This can be used to prevent damage to the part in case of open LED events. A programmable switching frequency offers flexibility in design for higher efficiency or reduced component size. Application includes display backlighting, automotive and avionic lighting.

• Operates in boost, SEPIC, buck mode and buck boost mode
• 128:1 internal exponential scale PWM dimming, 20000:1 external PWM dimming at 100Hz
• PMOS switch driver for PWM dimming, LED short/open protection and indication
• Constant voltage and constant current regulation
• Internal spread spectrum frequency modulation, easy synchronization to external clock
• Programmable VIN UVLO with hysteresis
• Operating supply range from 3 to 60V (TA=25°C, VIN=EN/UVLO=12V)
• Typical quiescent current is 1.8mA (VFB=1.25V, not switching)
• Programmed switching frequency range from 1880 to 2120KHz (RT=45.3k SYNC/SPRD=0V)
• 16-lead plastic MSOP package, temperature range from -40°C to 125°C

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