LT3922IUFD#PBF

LINEAR TECHNOLOGY  LT3922IUFD#PBF  LED Driver, Buck-Boost, 2.8V to 36V input, 1 Output, 2 MHz Switch. Frequency, 40V/2A out, QFN-28 新

The is a synchronous step-up LED driver in 28 pin QFN package. This monolithic, synchronous, step-up DC to DC converter utilizes fixed frequency, peak current control and provides PWM dimming for a string of LEDs. The LED current is programmed by an analogue voltage or duty cycle of pulses at CTRL pin. The switching frequency is programmable from 200KHz to 2MHz by an external resistor at the RT pin or by an external clock applied at SYNC/SPRD pin. With optional spread spectrum frequency modulation enabled, the frequency varies from 100% to 125% to reduce EMI. The LT3922 also includes a driver for an external high side PFET for PWM dimming and an internal PWM signal generator for analogue control of PWM dimming when an external signal is not available. Additional features include an accurate external reference voltage for use with the CTRL and PWM pins, LED current monitor, accurate EN/UVLO pin threshold and thermal shutdown.

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±2% LED current regulation and ±2% output voltage regulation

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5000:1 PWM dimming at 100Hz, 128:1 internal PWM dimming

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Up to 34V LED string voltage and 2A, 40V internal switches

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Silent switcher architecture for low EMI

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Operates in boost, buck and buck-boost mode

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2.8V to 36V input voltage range and 2.9mA VIN pin quiescent current VEN/UVLO=1.5V, not switching

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Open-drain fault reporting for open circuit and short circuit load conditions

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Analogue or duty cycle LED current control

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Open/short LED protection and fault indication

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Operating temperature range from -40°C to 125°C