Santa Clara, Calif. - National Semiconductor's LM5025 is an active-clamp PWM controller for high-frequency forward converter topologies designed to boost the efficiency and power density of conventional forward regulators. Using the company's analog bipolar-CMOS-DMOS technology to cut external component count, the LM5025 integrates a 3-amp driver, 100-volt start-up bias regulator and a user programmable 1 MHz oscillator, and the chip exhibits a total propagation delay of less than 100 ns, thus suiting it to a variety of power supply applications for telecom. The LM5025 can be configured to provide either overlap time (for p-channel switch applications) or dead-off time (for n-channel switch applications).
"National's LM5025 complements our LM5000 family of high-voltage power ICs to offer no-compromise solutions to satisfy the escalating needs of our customers," said Paul Greenland, marketing director of National Semiconductor's power management group.
The active-clamp topology, which allows operation at duty cycles above 50 percent and a higher primary to secondary turns-ratio in the power transformer, is key to high-efficiency, zero voltage switching (ZVS) designs. The National chip is the second new active-clamp product this week, having arrived almost simultaneously with Texas Instruments' active-clamp UCC2891-2894 devices (see Dec. 19).
Shipping now, the LM5025 is offered in a LLP-16 or a TSSOP-16 package. It is priced at $1.30 each in 1k quantities.