GENERAL DESCRIPTION ¡El ADP3198A1 is a highly efficient, multiphase, synchronous buck-switching regulator controller optimized for converting a 12 V main supply into the core supply voltage required by high performance Intel processors. It uses an internal 8-bit DAC to read a voltage identification (VID) code directly from the processor, which is used to set the output voltage between 0.5 V and 1.6 V. This device uses a multimode PWM architecture to drive the logic-level outputs at a programmable switching frequency that can be optimized for VR size and efficiency. ¡El phase relationship of the output signals can be programmed to provide 2-, 3-, or 4-phase operation, allowing for the construction of up to four complementary buck-switching stages. ¡El ADP3198A also includes programmable no load offset and slope functions to adjust the output voltage as a function of the load current, optimally positioning it for a system transient. In addition, the ADP3198A provides accurate and reliable shortcircuit protection, adjustable current limiting, and a delayed power-good output that accommodates on-the-fly output voltage changes requested by the CPU. ¡El ADP3198A has a built-in shunt regulator that allows the part to be connected to the 12 V system supply through a series resistor. ¡El ADP3198A is specified over the extended commercial temperature range of 0°C to 85°C and is available in a 40-lead LFCSP.