The IRU3027 controller IC is specifically designed to meet VRM 9.0 specification for next generation microprocessor applications requiring multiple on-board regulators. The IRU3027 provides a single chip controller IC for the Vcore, three LDO controllers, one with an automatic select pin that connects to the Type Detect pin of the AGP slot for the AGP V DDQ supply, one for GTL+ and the other for the 1.8V chip set regulator as required for the next generation PC applications. The IRU3027 is designed to use either bipolar transistors for VOUT3(1.5V) and VOUT4(1.8V). No external resistor divider is necessary for any of the regulators. The switching regulator features a patented topology that in combination with a few external components as shown in the typical application circuit, will provide well in excess of 20A of output current for an on-board DC-DC converter while automatically providing the right output voltage via the 5-bit internal DAC. The IRU3027 also features loss-less current sensing for both switchers by using the RDS(ON) of the high side power MOSFET as the sensing resistor, an output under-voltage shutdown that detects short circuit condition for the linear outputs and latches the system off, and a Power Good window comparator that switches its open collector output low when any one of the outputs is outside of a pre-programmed window.