LT3922EUFD#PBF

LT3922 is a monolithic, synchronous, step-up DC/DC converter that 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 the duty cycle of pulses at the CTRL pin. It will maintain ±2.5% current regulation through an external sense resistor over a wide range of output voltages. The switching frequency is programmable from 200KHz to 2MHz by an external resistor at the RT pin or by an external clock applied at the SYNC/SPRD pin. With the optional spread spectrum frequency modulation enabled, the frequency varies from 100% to 125% to reduce EMI. It also includes a driver for an external high side PMOS for PWM dimming and an internal PWM signal generator for analogue control of PWM dimming when an external signal is not available. It is used in application such as automotive and industrial lighting, machine vision etc.

• ±2% output voltage regulation, programmed switching frequency is 2000KHz typical
• 5000:1 PWM dimming at 100Hz
• 128:1 internal PWM dimming
• Spread spectrum frequency modulation, Silent Switcher® architecture for low EMI
• Operates in boost, buck mode and buck-boost mode
• Input voltage range is 2.8V to 36V
• Upto 34V LED string voltage, 2A, 40V internal switches
• Analog or duty cycle LED current control, open/short LED protection and fault indication
• Operating temperature is -40°C to 125°C
• Package style is 28-lead plastic QFN

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