Product category: Power Supply ICs and Controllers
News Release from: National Semiconductor | Subject: LM5071
Edited by the Electronicstalk Editorial Team on 17 January 2006
Power chip offers alternative source for
PoE
A new single-chip power device is specifically designed for power over Ethernet (PoE) devices that operate from alternative power sources or the PoE-enabled network.
National Semiconductor has developed the industry's first single-chip solution specifically designed for power over Ethernet (PoE) devices that operate from alternative power sources or the PoE-enabled network The LM5071 is a powered device (PD) interface and DC/DC convertor IC that simplifies the design of a variety of PoE applications that require an auxiliary power source such as an AC adapter
This article was originally published on Electronicstalk on 5 Jan 2001 at 8.00am (UK)
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Devices powered by a PoE network include IP phones, security cameras and wireless local area network (WLAN) nodes connected through Ethernet networking cables and ports.
Operating these PoE devices from alternate power sources is often necessary to relieve the burden on the power sourcing equipment (PSE) or to operate the device on a network that is not PoE-enabled.
Existing solutions limit the choice of auxiliary power sources, which can drive up overall system cost or complexity.
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National's LM5071 is the industry's first single-chip IEEE802.3af-compliant PD interface port and pulsewidth modulator (PWM) controller specifically designed to accept power from external AC adapters.
The LM5071 integrates a PD front end that accepts power from the PSE or auxiliary power to a single chip with a DC/DC controller that steps down the input voltage to power various PD loads.
"Powering the device from an AC adapter can be tricky and requires forethought by the IC designer".
"The LM5071 solves the auxiliary power interface problem encountered by many PoE equipment designers with an elegant, integrated PD solution", said Paul Greenland, Director of Strategic Marketing for National Semiconductor's Power Management group.
"This new addition to National's PoE power product family accepts a wide range of AC adapter voltages, giving equipment designers the flexibility to optimise total system cost".
"The LM5071 builds on the success and learnings of its predecessor, the LM5070, to provide an auxiliary-powered PD solution that is superior to any on the market today".
The LM5071 is fabricated with National's ABCD150-XV1 high-voltage analogue bipolar/CMOS/DMOS technology and offers advantages such as an integrated, high-frequency, current-mode DC/DC controller, user-programmable undervoltage threshold and hysteresis, and a highly accurate fault current control loop.
It features a maximum input voltage of 80V, user-programmable oscillator frequency up to 1MHz and overtemperature protection, plus a voltage reference and high-performance error amplifier for nonisolated applications.
National's LM5071 is available in lead-free and standard small-footprint TSSOP-16 packages.
The product is priced at $1.45 each in 1000-unit quantities.
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