EL SEGUNDO, Calif. — February 2006 — International Rectifier, IR®(NYSE: IRF), a world leader in power management technology, today expanded the IR XPhase^® family of scalable multi-phase converter chip set devices with the IR3084 and IR3084U XPhase Control ICs. The new Control ICs are designed to be used with IR’s existing IR3086A Phase IC and companion DirectFET® power MOSFETs such as the IRF6617 and IRF6691 to achieve as much as three percent higher efficiency in 130A applications with seven phases, compared to competing five-phase designs.

The IR3084 supports Intel® VR10.x and VR11 microprocessor core power requirements, while the IR3084U is a universal voltage identification (VID) device for VR10.x and VR11 as well as AMD Opteron™ VID codes and start-up sequences.

The XPhase chip set is designed to increase power density and efficiency in desktops, servers, voltage regulator modules (VRM) and embedded systems. By increasing the number of phases from five to seven, the current in each phase is decreased, and enables the use of smaller inductors and reduced output capacitors. This enables a reduction in footprint size from 3200mm2 to 2400mm2, a 25% reduction in board area.

The seven-phase IR3084 solution including the IRF6617 and IRF6691 power MOSFETs achieves 88% efficiency at full load current and eliminates the need for a heatsink.

“Removal of the regulator heatsink reduces manufacturing costs and improves airflow to the CPU in low-profile 1U and blade servers. This improves system performance and long-term product reliability,” said Faisal Ahmad, marketing manager for DC-DC Computing Products at International Rectifier.

Both Control ICs include 0.5% overall system accuracy and differential remote voltage sensing. The ICs offer a programmable 150kHz to 1MHz oscillator, remote temperature sensing, and loss-less DCR current sensing with programmable hiccup over-current protection. The IR3084U includes a VID select pin which allows for simple migration from AMD to Intel VID codes.

XPhase is IR's distributed multiphase architecture that consists of control ICs and phase ICs that communicate using a simple five-wire bus scheme. Phases can be added or removed without changing the fundamental design. The five-wire analog bus consists of bias voltage, phase timing, average current, error amplifier output and VID voltage. By eliminating point-to-point wiring between the control and the phase ICs, the five-wire bus shortens interconnections, and reduces parasitic inductance and noise. This simplifies PCB layout and gives a more robust design.

The IR3084 and IR3084U data sheet is restricted to VR11 licensees only.

Please contact Chris Bull via e-mail, for more information.

XPhase Chipset Using the New IR3084 Series Control ICs
	Part Number	Function	Package	Switching Frequency
NEW	IR3084	XPhase® Control IC, VR10.x and VR11	28L MLPQ 5x5	150kHz – 1MHz
NEW	IR3084U	Universal XPhase® Control IC, VR10.x, VR11, and AMD Opteron	28L MLPQ 5x5	150kHz – 1MHz
—	IR3086A	Phase IC, One to X Phases	20L MLPQ 4x4	—

Recommended MOSFETs for Use with the IR3084 & IR3084U
Part Number	Function	Package	BVDSS (V)	RDS(on) max @10V (mOhm)	RDS(on) max @4.5V (mOhm)	VGS (V)	ID @ Tc=25ºC (A)	QG typ (nC)	QGD typ (nC)
IRF6617	Control FET	DirectFET® ST	30	8.1	10.3	20	55	11	4.0
IRF6691	Synchronous FET	DirectFET® MX	20	1.8	2.5	12	180	47	—

Availability and Pricing

The IR3084 and IR3084U XPhase control ICs are available immediately. Pricing is US $1.60 each for the IR3084MPbF and the IR3084MTRPbF (Tape & Reel), and US $1.75 each for the IR3084UMPbF and the IR3084UMTRPbF (Tape & Reel). Pricing is in 10,000-unit quantity. Prices are subject to change. The devices are lead-free (PbF) and RoHS (Restriction of Hazardous Substances) compliant.