IR Offers Control IC For Intel VR11.0 and VR11.1 Processor-Based Power Solutions

April 08, 2008 by Jeff Shepard

International Rectifier (IR)® introduced the IR3502 XPhase® control IC for Intel® VR11.0 and VR11.1 processors.

The IR3502 provides overall system control and interfaces with any number of IR’s XPhase® phase ICs, each driving and monitoring a single phase. The IR3502’s key features include 0.5% overall system set point accuracy and daisy-chain digital phase timing for accurate phase interleaving without the need for external components. Combined with the IR3507 phase IC, the IR3502 and IR3507 chipset provides the power state indicator (PSI) capability to improve voltage regulator module (VRM) light load efficiency.

"The IR3502 is 50% smaller than a traditional six-phase control IC in a 7mm by 7mm MLP package. Co-designed with the IR3507 phase IC and DirectFET® MOSFETs, the Xphase chipset provides higher power density compared to traditional multiphase architectures and results in a power supply that is smaller, less expensive, and easier to design," said Jeff Sherman, IR’s Senior Product Marketing Manager for Enterprise Power Products.

The IR3502 includes a host of protection features and a high level of programmability including programmable 250kHz to 9MHz clock oscillator frequency to provide per phase switching frequency of 250kHz to 1.5MHz, programmable dynamic VID slew rate and programmable VID offset or no offset, in addition to high speed error amplifier with wide bandwidth of 30MHz and fast slew rate of 10V/us. The IR3502 also features improved droop capability that reduces the potential need for an external thermistor.

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

Available in a small, thermally enhanced 32-lead 5 x 5mm MLPQ package, pricing for the devices begins at US$1.90 each in 10,000-unit quantities for the IR3502MTRPBF and US$1.75 each in 10,000-unit quantities for the IR3507MTRPBF.