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National Semiconductor Introduces Industry’s Highest-Power PoE PD Controller with Auxiliary Power Support

100V LM5073 Features Programmable DC Current Limit up to 800 mA

May 22, 2007

POWER CONVERSION AND INTELLIGENT MOTION CONFERENCE, NUREMBERG, Germany - May 22, 2007 — National Semiconductor Corporation (NYSE:NSM) today introduced a Power-over-Ethernet (PoE) powered- device (PD) controller with adjustable output current level and the ability to interface with any DC-DC converter topology.

The industry’s highest-power PoE controller, National’s new LM5073 integrates a programmable interface port including a hot-swap controller that exceeds the standard IEEE 802.3af specifications, allowing designers to operate PoE appliances at power levels of 30W or more.  For greater flexibility, the LM5073 separates the PD interface from the DC-DC converter to support a wide variety of isolated and non-isolated DC-DC converter topologies.  Applications include IP telephony, remote security cameras, card readers, wireless access points, PoE-enabled industrial automation systems and point-of-sale terminals.

From May 22-24, National will demonstrate the new LM5073 PoE controller in hall 12, booth 329 at the Power Conversion and Intelligent Motion (PCIM) Conference in Nuremberg, Germany.  PCIM is one of the industry’s leading forums for presenting and discussing power electronics and its applications in intelligent motion.

The LM5073 PoE controller supports PD designs that are fully compliant with the IEEE 802.3af standard.  If more power is required, the low RDS(ON) hot-swap MOSFET and programmable DC current limit extend the range of LM5073 applications to more than twice the power level of IEEE 802.3af compliant devices.  The LM5073 also provides the flexibility for the PD to accept power from unregulated auxiliary sources such as AC adapters and solar cells in a variety of configurations.  The 100V maximum voltage rating simplifies selection of the voltage suppressor that protects the PD from network transients.

The LM5073 joins National’s family of PoE devices, including the LM5072, which integrates a DC-DC controller with the higher PoE power capability of the LM5073, the LM5070, which integrates a 375 mA PoE interface circuit with a DC-DC controller, and the LM5071, a single chip solution specifically designed for PoE devices that operate from alternative power sources. National’s LM5073 can be used with the DP83848 single port or DP83849 dual port 10/100 Mbps Ethernet physical layer device to provide a space and cost effective system solution for PoE Ethernet compliant designs.  The power for the node (following the PoE standard) is supplied by standard CAT5 cable and connectors via the National devices, which eliminates the need for expensive external power supplies while delivering full Ethernet connectivity.

Technical Features of the New PoE Controller
Offered in a 14-pin TSSOP with exposed pad for improved thermal performance, the LM5073 integrates a 100V, 700 milli-Ohm, N-channel MOSFET as well as the PD signature and under-voltage lockout resistors.  It provides configurable front and rear auxiliary inputs that accept power from AC adapters to reduce the power draw on the PoE power sourcing equipment.  Complementary control outputs provide a flexible interface to the best DC-DC converter topology for the particular application.  For non-isolated applications, the LM5073 can be paired with National’s LM5007 and LM5010 buck regulators or popular LM5574, LM5575 and LM5576 high-voltage SIMPLE SWITCHER® product family.  For higher-power isolated systems, the LM5073 can be paired with National’s LM5020 or LM5026 pulse-width modulation (PWM) controllers.  For more information on the LM5073 or to order samples and an evaluation board, visit http://www.national.com/pf/LM/LM5073.html

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

Pricing and Availability
National’s new LM5073 is available now and priced at $1.30 in 1,000-unit quantities. 

Note to Editors:  To view a high-resolution downloadable photo of this product, visit National's photo gallery at http://www.national.com/company/pressroom/gallery/power.html.

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 and a variety of broad electronics markets, including medical, automotive, industrial, and test and measurement applications. Headquartered in Santa Clara, Calif., National reported sales of $2.16 billion for fiscal 2006, which ended May 28, 2006.  Additional company and product information is available at www.national.com