The US3021M controller IC is specifically designed to meet Intel specification for next generation microprocessor applications requiring multiple on board regulators . The US3021M provides a single chip controller IC for the Vcore , 3LDO controllers, one with the automatic select pin that connects to the TYPE DETECT pin of the AGP slot for the AGP Vddq supply, one for GTL+ and the other for the 1.8V chip set regulator as required for the next generation PC applications. The US3021M uses N ch MOSFET as pass transistor for Vout2(Vddq), Vout3(1.5V) and Vout4(1.8V). No external resistor divider is necessary for any of the regulators. The switching regulator feature 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 US3021M also features, loss less current sensing for both switcher 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.