Product Releases

IR’s New XPhase Chipset Enables Smaller, Simpler Design

Fri, 05/28/2010 - 7:01am

IR’s New XPhase Chipset Enables Smaller, Simpler DesignInternational Rectifier introduced the IR3521 and IR3529 XPhase chipset solution offering best-in-class efficiency over the entire load range for next-generation high performance AMD processors. 

The IR3521 XPhase control IC supports high speed (HS) I2C serial communications to provide overall system control, interfacing with any number of phase ICs, each driving and monitoring a single phase. When used with the IR3529 XPhase phase IC, the IR3521 enables phase dropping to significantly improve the light load performance of the power supply.

The IR3529 phase IC features a Power State Indicator (PSI) to maximize efficiency at light loads, as well as enhanced driver capability and reduced non-overlap time. Turbo is also included to improve load turn-on response. In addition, the IR3529 incorporates novel features that greatly enhance the transient response of the converter to reduce the overall solution size and cost.

“Combined with our DirectFET MOSFETs, our new XPhase chipset for AMD processors delivers a power supply that is smaller, more flexible, and easier to design while providing superior efficiency over the entire load range compared to conventional approaches,” said Deepak Savadatti, senior director, IR’s Multiphase Products, Enterprise Power Business Unit.

The IR3521 control IC provides outputs for both the VDD core and VDDNB auxiliary planes required by the AMD CPU and features high speed error amplifiers with wide bandwidth of 20MHz and fast slew rate of 10V/us. Remote sense amplifiers provide differential sensing and require less than 50uA bias current. In addition, the new device offers a high level of programmability including programmable Dynamic VID slew rates, VID Offset (VDD output only), output impedance (VDD output only) and dynamic OC for IDD spike.

The IR3529 phase IC features anti-bias circuitry, 7V/4A gate drivers (6A GATE L sink current) and supports loss-less inductor current sensing and a converter output voltage up to 5.1 V. The new device also implements cycle-by-cycle over-current protection to resolve high repetition load transients.


Part Number


Set Point Accuracy

PSI Capability

Fsw(per phase)


32pin 5x5 MLPQ



0.25 – 1.5MHz

Part Number


GateH(Source/Sink), A

GateL(Source/Sink), A

PSI Capability


20pin 4x4 MLPQ






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