8-Bit Programmable 2- To 5-Phase Synchronous Buck Controller

The FAN5029 is a highly efcient multi-phase synchro- nous buck Switching Regulator controller optimized for converting a 12V main supply into the core supply volt- age required by high performance Intel processors. It uses an internal 8-bit DAC to read voltage identication (VID) code directly from the processor, which is used to set the output voltage between 0.5V and 1.6V. It uses a multi-mode PWM architecture to drive the logic-level out- puts at a programmable switching frequency that CAN be optimized for VR size and efciency. The phase relation- ship of the output signals CAN be programmed to provide 2-, 3-, 4-, or 5-phase operation, allowing for the construc- tion of up to ve complementary buck switching stages. The FAN5029 also includes programmable no-load off- set and slope functions to adjust the output voltage as a function of the load current, so that it is always optimally positioned for a system transient. The FAN5029 also pro- vides accurate and reliable short Circuit Protection adjustable current limiting, and a delayed Power Good output that accommodates on-the-y output voltage changes requested by the CPU. FAN5029 is specied over the extended commercial temperature range of 0C to +85C and is available in a 40-lead MLP package. By Fairchild Semiconductor