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SAN DIEGO , Oct. 22 /PRNewswire-FirstCall/ -- LEDs 2007 -- NationalSemiconductor Corporation (NYSE: NSM) today added two new light-emitting diode(LED) drivers to its PowerWise(R) energy-efficient product family. National'sLM3401 and LM3405A LED drivers power 1W to 5W, high-brightness LEDs found inindustrial and automotive applications as well as general illuminationapplications such as solid state and signage. Each offers a wide input voltagerange and provides a constant current to regulate the LED brightness and lowfeedback voltage to minimize power dissipation.
Featuring a voltage range from 4.5V to 35V, National's high-efficientLM3401 LED driver includes a scalable current drive of greater than 3A and a100 percent duty cycle. A low feedback voltage of 0.2V and accuracy within 3percent provides a constant current to provide constant color output from anLED.
The LM3405A LED driver features a voltage range from 3V to 22V and is ableto regulate from a loosely coupled 12V AC rail found in industrial andcommercial lighting applications. The small SOT-23 package allows LEDs to beplaced into small-form factor light bulbs to offer higher efficiency versusthe traditional halogen and incandescent sources for illumination.
National's two new LED drivers will be shown in National's booth #26 atthe LEDs 2007 conference in San Diego from Oct. 24 to 27.
Technical Features of the LM3401 LED Driver
The LM3401 is a high-efficiency hysteretic PFET switching controller thatprovides a high-performance, constant current drive to a string of LEDsresulting in a constant color output. An adjustable hysteretic window allowsfor flexibility in component selection and overall design simplicity. Noexternal compensation is required. The regulated LED current is sensed and iscompared to the reduced feedback of 0.2V for current sensing which eliminatesthe need for an output capacitor. Offered in an 8-pin mini SOIC package, theLM3401 has programmable over current voltage protection and a DIM input pinfor PWM inputs to control dimming. For more information on the LM3401 or toorder samples and an evaluation board, visithttp://www.national.com/pf/LM/LM3401.html.