FEATURES
n n n n n n n n n n n n DESCRIPTION
The LT®3474/LT3474-1 are fixed frequency step-down DC/DC converters designed to operate as constant-current sources. An internal sense resistor monitors the output current allowing accurate current regulation, ideal for driving high current LEDs. High output current accuracy is maintained over a wide current range, from 35mA to 1A, allowing a wide dimming range. Unique PWM circuitry allows a dimming range of 400:1, avoiding the color shift normally associated with LED current dimming. The high switching frequency offers several advantages, permitting the use of small inductors and ceramic capacitors. Small inductors combined with the 16-lead TSSOP surface mount package save space and cost versus alternative solutions. The constant switching frequency combined with low-impedance ceramic capacitors result in low, predictable output ripple. With their wide input range of 4V to 36V, A current mode PWM architecture provides fast transient response and cycle-by-cycle current limiting.
Linear Technology
