Fairchild's CPU Power Solution Addresses VRM10 and Beyond

The FAN5019 reads the voltage identification (VID) code directly from the processor and sets the output voltage between 0.8375 and 1.6V. In addition, sophisticated control circuitry accommodates on-the-fly output voltage changes requested by the CPU without introducing voltage glitches on the output.

Tight Load Line Accuracy, Low System Cost and Part Count

Unlike competitor's products that use MOSFET R_DS(on) (inaccurate) or sense resistors (expensive) to measure current and set the load line, Fairchild's solution uses temperature-compensated inductor current sensing for the programmable load line-providing tight accuracy at the lowest system cost.

Intel-platform processors also require fast load transient response at the CPU socket. The FAN5019's flexible PWM architecture provides a highly stable, high-speed control loop that meets Intel's tough transient requirements with the fewest possible output capacitors. It also uses active voltage positioning technology (droop) to further minimize the number of capacitors and their associated costs.

Flexible Phases for All Designs
To ensure that all phases carry an equal share of the load current (or thermal load), and to minimize the size of the external components, the FAN5019 provides active current sharing and current "steering" between phases. Phase current skewing can be externally programmed to compensate for layout asymmetry and for thermal balancing. The FAN5009 driver provides the interface and high current drive to control the external power MOSFETs for each phase. Output-signal phase relationships are programmable for 2-, 3-, or 4-phase operation, for the ultimate in scalability and flexibility.

The driver has a built-in output disable function, which allows for coordination with the controller and controlled shutdown with no negative voltage spikes on the CPU power supply rail. For additional safety and reliability, the controller features undervoltage, overvoltage, and short-circuit protection.

Small Packages for Tight Spaces
The FAN5019 is available in a 28-lead TSSOP package, and the FAN5009 is available in a SO-8 package. For pricing and availability information, see www.fairchildsemi.com/pf/FA/FAN5019.html & www.fairchildsemi.com/pf/FA/FAN5009.html.