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Bel Fuse Selects Intersil's Advanced Power ICs for Datacom and Telecom Point of Load Power Modules

-- Intersil Endura power ICs solve voltage regulation problem for pre-biased loads while reducing circuit complexity and costs offering the industry's highest performance-to-price ratio

MILPITAS, CA, January 12, 2004 – Intersil Corporation (NASDAQ: ISIL), a world leader in the design and manufacture of high performance analog solutions, today announced that Bel Fuse Inc (NASDAQ: BELFA & BELFB) has selected Intersil Endura™ power ICs for their new point-of-load (POL) power modules designed to power high-current ASICs and FPGAs for the datacom/telecom markets. Intersil worked closely with Bel to design PWM controllers and MOSFET drivers that overcome the difficulties associated with voltage regulators having to start up into pre-biased voltage planes for FPGAs and ASICs increasingly used in datacom/telecom applications.

“Regulating a pre-biased load is tricky business,” said Steve Rivet, Senior Marketing Manager for Intersil’s Desktop/Server Power Products. “Pre-biasing means that voltage is present at the load even when the load, such as an ASIC, is shut down. During soft start, a synchronous buck dc/dc converter must be capable of disabling its low-side MOSFET, so that it does not sink current from the disabled power plane. This way it avoids causing perturbations in the system, such as voltage glitches. Our new ISL6608 MOSFET driver IC was designed specifically to overcome this problem.”

“Point-of-load voltage regulation for high-current FPGAs or ASICs that are in a pre-biased condition requires the power management IC supplier to have a thorough understanding of the problem and its path to resolution,” said Mark Masera, Director of Engineering for Bel. “Intersil worked with us to understand this problem and developed a solution that actually reduces cost and complexity while yielding high performance in the face of pre-biased loads. This has enabled us to achieve our customer’s required performance objectives while meeting aggressive price targets.”

Two common conditions lead to a pre-biased load:

• A components I/O voltage, typically 3.3 V, may be up before the CPU or FPGA core voltage and forward biases isolation diodes charging the core voltage supply input capacitors.
• The FPGA may be completely powered down but has voltages on its input pins from other equipment. This voltage forward biases ESD diodes charging the core and I/O supplies input capacitors.

A voltage regulator must be able to power up into a pre-biased load by disabling its lower FET while in soft start. In this condition, the synchronous multiphase buck converter acts as a standard buck converter.

The key element in overcoming the pre-bias problem is Intersil’s new Endura ISL6608 MOSFET driver IC. The ISL6608 is optimized to drive two N-channel power MOSFETs in a synchronous-rectified buck converter topology. During soft start, the ISL6608 acts as a standard-buck driver in a diode emulation mode, disabling the lower MOSFET temporarily. Light-load converter efficiency and pre-biased load startup are enhanced by the ISL6608’s diode emulation feature. When diode emulation is enabled, the driver allows discontinuous conduction by detecting when the inductor current reaches zero and subsequently turns off the low-side MOSFET. This prevents the output from sinking current and avoids the generation of a negative transient.

Bel’s datacom/telecom POL modules incorporate Intersil’s Endura ISL6553 high-precision two-phase PWM IC controlling two ISL6608 MOSFET drivers. The high degree of integration of these ICs provides a full range of performance and protection features that yield the industry’s highest performance-to-price ratio. Other Intersil HIP63XX or ISL65XX multiphase PWM controllers could also be used to form a precision multiphase voltage regulator solution with high-frequency switching and high-current capability.

About Bel Fuse Inc
Bel and its subsidiaries are primarily engaged in the design, manufacture and sale of products used in networking, telecommunications, high-speed data transmission, automotive and consumer electronics. Products include magnetics and connectors for voice and data transmission, fuses, DC/DC converters, delay lines and hybrid circuits. The Company operates facilities around the world. (www.BelFuse.com) About Intersil
Intersil Corporation is a leader in the design and manufacture of high performance analog semiconductors. The company’s products address three of the industry’s fastest growing markets - flat panel displays, optical storage (CD and DVD recordable) and power management. Intersil products include power management devices for battery management, hot-swap and hot-plug controllers, linear regulators, supervisory ICs, switching DC-DC regulators and power MOSFET drivers; optical storage laser diode drivers; DSL line drivers; video and high performance operational amplifiers; data converters; interface ICs; analog switches and multiplexers; crosspoint switches; voice-over-IP devices; and ICs for military, space and rad-hard applications. For more information about Intersil or to find out how to become a member of our winning team, visit the company’s web site and career page at: www.intersil.com.

This release may include "forward looking statements" that are subject to risks and uncertainties. For information identifying economic, political, climatic, currency, regulatory, technological, competitive and some other important factors that could cause actual results to differ materially from those anticipated in the forward looking statements, see Intersil’s Safe Harbor Forward Looking Statement disclaimer found at http://www.intersil.com/legal.asp, as well as Intersil’s SEC filings as updated from time to time, found at http://www.sec.gov. Endura is a trademark of Intersil Americas Inc.
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