New Industry Products

National Adds Controllers for PoE and Half-Bridge D2Ds

March 20, 2006 by Jeff Shepard

During this week's Applied Power Electronics Conference, National Semiconductor Corp. introduced two new controllers, the LM5072, designed for use with high-power PoE (power over Ethernet) powered devices, and the LM5035, designed for use with eighth-, and sixteenth-brick half-bridge dc-dc (D2D) converter modules.

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 (up to 25W) than standard IEEE 802.3af devices.

The LM5072 joins National's 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 powered devices (PDs) 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.

The LM5035, also introduced at APEC, integrates a voltage-mode pwm controller with high-side and low-side 2A peak gate drivers plus two programmable, secondary-side synchronous rectifier FET drivers. Programmable control of the rectifying switches allows designers to perfect their timing relationship to optimize overall power efficiency. Applications for LM5035 half-bridge power supplies include telecommunications, data communications and industrial control systems where power density and efficiency are primary concerns.

"Most competitors' half-bridge controllers require an external half-bridge FET driver, which increases the solution footprint and introduces timing errors due to propagation delays," said Paul Greenland, director of strategic marketing for National Semiconductor's Power Management Group. "With the LM5035, National has integrated core IP from our LM5100A gate driver and LM5025 pwm controller on a single chip. The result is a robust solution with industry-leading power density for highly compact power modules such as one-eighth and one-sixteenth bricks."

Both devices are currently available. The LM5072 is priced at $1.85, the LM5035 is priced at $1.90, both in 1,000-unit quantities.