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Description

The LM3405A is a 1A constant current buck LED driver designed to provide a simple, high efficiency solution for driving high power LEDs. With a 0.205V reference voltage feedback control to minimize power dissipation, an external resistor sets the current as needed for driving various types of LEDs. Switching frequency is internally set to 1.6MHz, allowing small surface mount inductors and capacitors to be used. The LM3405A utilizes current-mode control and internal compensation offering ease of use and predictable, high performance regulation over a wide range of operating conditions. With a maximum input
voltage of 22V, it can drive up to 5 High-Brightness LEDs in series at 1A forward current, with the single LED forward voltage of approximately 3.7V. Additional features include user accessible EN/DIM pin for enabling and PWM dimming of LEDs, thermal shutdown, cycle-by-cycle current limit and over-current protection.

FEATURES
• VIN Operating Range of 3V to 22V
• Drives up to 5 High-Brightness LEDs in Series at 1A
• Thin SOT-6 package and VSSOP-8 PowerPAD Packages
• 1.6MHz Switching Frequency
• EN/DIM Input for Enabling and PWM Dimming of LEDs
• 300mΩ NMOS Switch
• 40nA Shutdown Current at VIN= 5V
• Internally Compensated Current-mode Control
• Cycle-by-cycle Current Limit
• Input Voltage UVLO
• Over-current Protection
• Thermal Shutdown