EL SEGUNDO, Calif. — November 2005 — International Rectifier, IR® (NYSE: IRF), a world leader in power management technology, today announced a three-phase PWM control IC with integrated drivers for DC-DC converters. The IR3094MPbF enables up to 40% circuit size reduction when used with International Rectifier DirectFET® MOSFETs. The smaller footprint makes the IR3094 ideal for space-constrained applications like DDR memory in rack servers and point-of-load (POL) modules used in high-density data systems.

A typical 80A, three-phase synchronous buck solution would require as many as 13 devices including one control and three drivers in addition to three MOSFETs per phase. A chip set made with the IR3094 plus IRF6637 and IRF6678 DirectFET MOSFETs reduces the silicon component count to seven devices for the same output current. Three pairs of these DirectFET MOSFETs can be placed directly next to the IR3094, creating a solution that minimizes printed circuit board trace parasitics and enables optimum switching performance.

“The IR3094 enables 80A POL regulators that take up less than two square inches of board space. This is critical as OEMs continue to push for increased density and functionality in next generation servers,” said Faisal Ahmad, marketing manager for DC-DC Computing Products at International Rectifier.

The IR3094 is designed for applications requiring a 0.85V to 5.1V output. The new IC is housed in a compact 7mm x 7mm MLPQ package, and features 3A gate drive capability, a 1% accurate reference voltage, adaptive voltage positioning and programmable switching frequency up to 540kHz. The IR3094 provides system protection with programmable soft start, hiccup over-current protection, over-voltage protection, and a “power good” indicator.

The IRF6678, an ideal synchronous MOSFET, features a very low typical device on-resistance of 1.7mOhm at 10VGS and 2.3mOhm at 4.5VGS. The IRF6637 is best suited as a control MOSFET, with very low Miller charge of only 4nC and typical device on-resistance of 5.7 mOhm at 10VGS and 8.2mOhm at 4.5VGS. Both MOSFETs are housed in the medium can DirectFET package, occupying the same board area as a SO-8 with only a 0.7mm profile, and improved thermal performance through double-sided cooling.

“The integrated high current gate drivers in the IR3094 combined with the optimized DirectFET pair creates a power management solution that delivers unparalleled integration and density for high-current point of load converters,” Ahmad added.

Part Number	Package	FSW (Hz)	VIN (V)	VOUT (V)	IOUT (A)
IR3094MPbF	7 x 7 MLPQ	100K - 540K	7.5 - 16	0.85 - 5.1	80A

Recommended MOSFETs for Use With the IR3094
Part Number	Package	Function	BVDSS (V)	RDS(on) typ @10V (mOhm)	RDS(on) typ @4.5V (mOhm)	VGS (V)	ID @ Tc=25ºC (A)	QG typ (nC)	QGD typ (nC)
IRF6678	DirectFET® MX	Synch FET	30	1.7	2.3	20	150	43	15
IRF6637	DirectFET® MP	Control FET	30	5.7	8.2	20	59	11	4

Availability and Pricing

The new IR3094MPbF PWM controller IC and the companion DirectFET MOSFETs are available immediately. Pricing is US $2.34 each for the IR3094, while the IRF6678 is US $1.25 each and the IRF6637 is US $0.91 each. All pricing is in 10,000-unit quantities, and is subject to change. The IR3094 and the DirectFET MOSFETs are RoHS compliant.