National Semiconductor Introduces First Single-Chip, High-Performance Power over Ethernet Solution

As the name implies, PoE networks power devices such as IP phones, security cameras, wireless local area network (WLAN) nodes and even musical instruments through Ethernet networking cables and ports. While competitive solutions use two or three chips, National's LM5070 is the industry's first single-chip PD interface port and pulse-width modulator (PWM) controller that meets the IEEE 802.3af standard. The LM5070 integrates an 80V, 400mA line connection switch and associated PoE interface circuits with a dc-dc controller that steps down the 48V input to power various loads.

"The LM5070 marks National's breakthrough entry into one of the most exciting, fastest-growing global markets available," said Edward Lam, vice president of National Semiconductor's Power Management group. "This single- chip product combines National's strengths in analog, power management, Ethernet networks, ultra-small packaging and process technologies to create an elegant solution that is clearly superior to anything on the market today."

Key Technical Specifications

The LM5070 is built at National's state-of-the-art fabrication facilities in Greenock, Scotland, and Arlington, Texas, using the company's ABCD150-XV1 high-voltage analog Bipolar/CMOS/DMOS process technology. This highly integrated product offers advantages such as an integrated, high-frequency, current-mode dc-dc controller, user-programmable under-voltage threshold and hysteresis, and a highly accurate fault current control loop. It features a maximum operating voltage of 75 volts, user-programmable oscillator frequency up to 1 MHz and over-temperature protection, plus a voltage reference and high-performance error amplifier for non-isolated applications.

Compelling Features and Benefits

National's LM5070 has a number of unique characteristics that make it easy to design in:

  -- UVLO Threshold and Hysteresis:  Designer can program the under-voltage
     lockout (UVLO) trip-point and hysteresis completely independently. This
     allows him or her to control start-up line currents and program the
     start and stop voltage points as desired for a variety of system
     applications.
  -- Inrush Current Programming: Allows designer full control over inrush
     transient, which is programmed to the current desired via an external
     resistor on the RCLP pin. Alternatively, if the default inrush limit
     (375mA) is desired, no external components are required -- the designer
     simply leaves the RCLP pin open.
  -- Internal Power Sequencing: The designer does not have to control the
     dc-dc converter system with "power good" signals or any other external
     communications interface.  Communication between the POE PD interface
     section and the dc-dc converter is completely integrated within the
     LM5070.
  -- Controls Isolated or Non-Isolated dc-dc Converters:  Integrates the
     precision voltage reference and error amplifier for dc-dc feedback in
     non-isolated converters.  Provides pull-up for opto-coupler transistor
     in isolated designs.
  -- Signature Resistor Disconnect:  The 25Kohm signature resistor is
     disconnected after PD detection to avoid power and efficiency losses.
  -- Programmable Oscillator Frequency: The oscillator for the switching
     regulator controller is fully user-programmable, easing power supply
     control loop design and allowing the user to maximize regulator
     performance.

  Power Over Ethernet: A Fast-Growing Global Market

Power over Ethernet solutions are rapidly growing in popularity. Because PoE devices do not require wall-mounted power supplies, overall systems costs are lower. For Internet Protocol (IP) telephony, uninterruptible power supplies (UPS) guarantee higher reliability and less susceptibility to power surges, theft, interruption or disconnection. In addition, the worldwide usage of the RJ-45 power connector ensures global compatibility of PoE devices. For wireless access point applications, these systems do not require AC power sources, power lines or outlets. Finally, PoE-enabled devices offer superior management flexibility with remote power up/down capability. According to research firm Venture Development Corp., the global market for PoE-enabling silicon ICs is expected to grow from an estimated 133 million units in 2004 to 496 million units in 2007, a 55 percent compound annual growth rate.

About National's Power Management Products

National Semiconductor is the number one supplier of power management ICs with 12.8 percent market share, according to iSuppli's 2004 voltage regulator/reference survey. National's power management revenue grew 29.7 percent in 2003 over the previous year, compared to 17.3 percent growth for the industry during the same time period. National's 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's WEBENCH(R) online design tool allows designers to select a power management product, create and analyze a design, and then build custom prototypes that can be delivered within 24 hours. More information about National's power management products is available at http://power.national.com/.

Pricing and Availability

National's LM5070 is available in small-footprint LLP-16 or TSSOP-16 packages. Lead-free package options are also available. The product is priced at $1.75 each in 1,000-unit quantities. More information is available at http://www.national.com/pf/LM/LM5070.html. A high-resolution downloadable photo of the products is available at http://www.national.com/company/pressroom/gallery/power.html.

About National Semiconductor

National Semiconductor, the industry's premier analog company, creates high performance analog devices and subsystems. National's leading-edge products include power management circuits, display drivers, audio and operational amplifiers, and data conversion solutions. National's key markets include wireless handsets, displays, PCs, networks and a broad range of portable applications. With headquarters in Santa Clara, California, National reported sales of $1.98 billion for fiscal 2004, which ended May 30, 2004. Additional company and product information is available at http://www.national.com/.

WEBENCH and National Semiconductor is a registered trademark of National Semiconductor Corporation. All other brands or product names are trademarks or registered trademarks of their respective holders.

CONTACT: Megan Carter of National Semiconductor, +1-408-721-6929 or
megan.carter@nsc.com

Web site: http://www.national.com/