Optimized for Industrial and Automotive LED Applications, New Family Provides Constant Current Through LEDs and Features Low Feedback Voltage to Minimize Power Dissipation
National Semiconductor introduced a family of LED drivers designed to power the new generation of 1 W to 5 W, high-brightness LEDs found in automotive, industrial and general illumination applications. National’s LM3402, LM3404 and LM3405 LED drivers offer the wider input voltage range required by this fast-growing market segment. In addition, National’s new LED drivers provide a constant current to regulate the LED brightness and low feedback voltage to minimize power dissipation.
Optimized for 1 W LEDs, National offers two versions of the LM3402 LED driver that provide wide input voltage ranges of either 6 V to 42 V or 6 V to 75 V. For 3 W and 5 W LEDs, the LM3404 and LM3405 have additional output current drive capability.
Technical Features of the LED Drivers
The LM3402 is a compact, constant-current buck regulator with up to 95 percent efficiency that drives up to 525 mA of current. Offered in an 8-pin mini SOIC package, the LM3402 has an enable pin that also can be used for dimming via pulse-width modulation (PWM) inputs and a reduced feedback of 0.2 V for current sensing. The LM3402‘s input voltage ranges from 6 V to 42 V. For higher input voltages, the LM3402HV offers the same features and a 6 V to 75 V voltage range.
Offered in an 8-pin SOIC narrow package, the LM3404 and LM3404HV share the same functionality as the LM3402 and LM3402HV, but have the ability to drive currents up to 1.2 A. These products are well-suited to power 3 W and 5 W LEDs at current levels of 700 mA or 1A, respectively.
Offered in an 8-pin mini SOIC package and a tiny 6-pin SOT-23 package, the LM3405 constant-current buck regulator delivers up to 1 A of current to drive 3 W or 5 W LEDs. With a 0.2 V reference voltage for constant-current feedback control and a switching frequency that is internally set to either 550 kHz or 1.6 MHz, the LM3405 provides a simple, highly-efficient solution for driving LEDs. In addition, the LM3405 has an input voltage range of 3 V to 22 V, is internally compensated and has an En/Dim pin for PWM dimming.
Pricing and Availability
The LM3402 and LM3402HV are available now in production quantities. Prices for these LED drivers start at $1.35 for the LM3402 and $1.65 for the LM3402HV in 1,000-unit quantities.
