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National Semiconductor Introduces Industryís First Single-Chip Power over Ethernet Controller for Higher-Power PoE Applications


100V LM5072 Integrates Power Interface Port and PWM Controller; Also Supports Applications that Operate from Auxiliary Power Sources such as AC Adaptors

March 20, 2006 -- National Semiconductor Corporation (NYSE: NSM), a worldwide leader in power management technology, today introduced its latest Power over Ethernet (PoE) device, the industryís first single-chip PoE controller for higher-power PoE applications. The LM5072, which integrates a programmable power interface port and a pulse-width modulation (PWM) controller, allows designers to operate PoE appliances at higher power levels than standard IEEE 802.3af devices.

National designed the LM5072 with programmable current limiting that allows it to draw up to 25W from a PoE-enabled port, since many emerging PoE applications require power that exceeds the limit of the existing standard. For standard 802.3af Powered Devices (PDs), the current may be programmed to any value between 150 mA and 800 mA, or the programming resistor can be simply disconnected to switch the LM5072 to the default mode with 440 mA maximum current draw. The LM5072, which has maximum input voltage and current ratings of 100V and 800 mA, also supports applications that accept power from auxiliary sources. National is demonstrating the LM5072 in booth 8/9 at the Applied Power Electronics Conference (APEC) in Dallas today through Wednesday.

The LM5072 joins Nationalís 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. Applications for the LM5072 include VoIP phones, remote security cameras, card readers, wireless access points, computer telephony, PDs in PoE systems and 48V telecom power supply controls.

ďNationalís LM5072 responds to the increasing market demand for complete solutions for higher-power PoE applications, as well as for devices that can be powered from auxiliary power sources,Ē said Paul Greenland, director of strategic marketing for National Semiconductorís Power Management Group. ďWith the addition of the LM5072 to our family of PoE products, National can provide designers with an integrated, single-chip PD solution to their PoE design challenges, whether those applications are for 802.3af networks or for customized, higher-power PoE systems.Ē

About the LM5072
The LM5072ís PoE port input and internal PD interface MOSFET are specified to an absolute maximum voltage of 100V. Designers can set the port current limit to the default 802.3af level or program it from 100 mA to 800 mA. The in-rush current limit defaults to 150 mA, but can be programmed over the same range as the port current limit. The precision 25 Kohm signature detection resistor is also integrated within the LM5072. The LM5072ís fully configurable AC adapter interface allows designers to connect auxiliary power to either the front-end PoE port or rear DC-DC converter. With a rear auxiliary supply, the LM5072 can disable the PoE interface to reduce power drawn from the Power Sourcing Equipment (PSE) when auxiliary power is applied.

The LM5072ís PWM controller includes a high-voltage bias regulator, programmable soft-start and programmable switching frequency with clock synchronization capability. The LM5072 is available with either 50 percent or 80 percent maximum PWM duty cycle, which allows the controller to support a variety of DC-DC converter topologies and operation over an extended auxiliary supply-voltage range. The LM5072 includes a two-percent-accurate voltage reference and error amplifier for direct control of the output in non-isolated DC-DC applications.

The LM5072 is offered in the thermally enhanced 16-pin TSSOP-EP package.

About Nationalís Power Management Products
National Semiconductor is the number one supplier of power management ICs with 14.1 percent market share, according to iSuppliís 2005 voltage regulator/reference survey. Nationalís power management revenue grew 37.3 percent in 2004 over the previous year, compared to 24 percent growth for the industry. Nationalís innovative power management products include best-in-class linear regulators; power monitoring, control and reference ICs; and switching converters, such as high-voltage ICs for DC-DC conversion, switched capacitor converters, lighting management ICs and inductive switching converters. National also offers online tools that enable power designers to select the best power management chips for their applications. Nationalís Webenchģ design tool allows designers to choose a product, create and analyze a design, and then build custom prototypes that can be delivered within 24 hours. More information about Nationalís power management products is available at

Pricing and Availability
Available now, the LM5072 is priced at $1.85 in 1,000-unit quantities. For more information about the LM5072, including how to order samples and evaluation boards, please visit the product folder.

Note to editors: To view a high-resolution downloadable photo of this product, visit Nationalís photo gallery.

About National Semiconductor
National Semiconductor, the industryís premier analog company, creates high-value analog devices and subsystems. Nationalís leading-edge products include power management circuits, display drivers, audio and operational amplifiers, communication interface products and data conversion solutions. Nationalís 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, California, National reported sales of $1.91 billion for fiscal 2005, which ended May 29, 2005. Additional company and product information is available at

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