Products, Materials + Tools | Jul 26, 2010

National Semiconductor Announces Highly Integrated, High-Brightness LED Drivers with Wide Input Voltage Range

National Semiconductor Corporation (NYSE:NSM) today added two new light-emitting diode (LED) drivers to its PowerWise® energy-efficient product family. National’s LM3401 and LM3405A LED drivers power 1W to 5W, high-brightness LEDs found in industrial and automotive applications as well as general illumination applications such as solid state and signage. Each offers a wide input voltage range and provides a constant current to regulate the LED brightness and low feedback voltage to minimize power dissipation.

Featuring a voltage range from 4.5V to 35V, National’s high-efficient LM3401 LED driver includes a scalable current drive of greater than 3A and a 100 percent duty cycle.  A low feedback voltage of 0.2V and accuracy within 3 percent provides a constant current to provide constant color output from an LED.  

The LM3405A LED driver features a voltage range from 3V to 22V and is able to regulate from a loosely coupled 12V AC rail found in industrial and commercial lighting applications.  The small SOT-23 package allows LEDs to be placed into small-form factor light bulbs to offer higher efficiency versus the traditional halogen and incandescent sources for illumination.

National’s two new LED drivers will be shown in National’s booth #26 at the 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 that provides a high-performance, constant current drive to a string of LEDs resulting in a constant color output.  An adjustable hysteretic window allows for flexibility in component selection and overall design simplicity.  No external compensation is required.  The regulated LED current is sensed and is compared to the reduced feedback of 0.2V for current sensing which eliminates the need for an output capacitor.  Offered in an 8-pin mini SOIC package, the LM3401 has programmable over current voltage protection and a DIM input pin for PWM inputs to control dimming.  For more information on the LM3401 or to order samples and an evaluation board, visit

Technical Features of the LM3405A LED Driver:
The new LM3405A extends the voltage range of National’s previously announced LM3405 up to 22V.  Offered in a tiny 6-pin SOT-23 package, the LM3405A constant-current buck regulator delivers up to 1A of current to drive 3W or 5W LEDs.  With a 0.2V reference voltage for constant-current feedback control, internal compensation and a fixed 1.6 MHz switching frequency, the LM3405A provides a simple, highly-efficient solution for driving LEDs.  The LM3405A also includes an EN/DIM pin for pulse-width-modulation (PWM) dimming.  The LM3405A drives general illumination for industrial and commercial lighting applications from the 12V AC and 12V DC rail. For more information on the LM3405A and LM3405 or to order samples and an evaluation board, visit

For more information on National’s lighting solutions, visit .

National also introduces the new LED WEBENCH tool for assistance in LED driver development: Read more  
About National’s Power Management Products:
National solves power management design problems in space- and energy-constrained applications from feature-rich handheld devices through large line-powered systems. From the novice power designer to the power expert, National’s products, people and design tools enable customers to design green-powered systems with complex power supplies in the shortest amount of time. High-performance products include switching regulators such as National’s flagship SIMPLE SWITCHER® family, and application-specific products including white-LED drivers and Power-over-Ethernet controllers. More information about National’s power management products is available at .

Availability and Pricing:
Available now, the LM3401 is priced at 75 cents each and the LM3405A is $1.30 in 1,000-unit quantities.

About National’s PowerWise Brand:
National’s PowerWise brand reflects the company’s energy-efficient product portfolio.  It signifies products with outstanding performance-to-power at the component level, as well as products that provide an outstanding, energy-efficient solution when coupled with other National parts.  National’s PowerWise family of products features energy-efficient power management, operational amplifiers, interface and data conversion products.  For more information about National’s PowerWise brand, visit: .

About National Semiconductor:
National Semiconductor, the industry's premier analog company, creates high-value analog devices and subsystems. National's leading-edge products include power management circuits, display drivers, audio and operational amplifiers, interface products and data conversion solutions. National's key analog markets include wireless handsets, displays, communications infrastructure, medical, automotive, industrial, and test and measurement applications. Headquartered in Santa Clara, Calif., National reported sales of $1.93 billion for fiscal 2007, which ended May 27, 2007. Additional company and product information is available at .