SC1112

Triple Low Dropout Regulator Controllers POWER MANAGEMENT Description The SC1112 was designed for the latest high speed motherboards. It includes three low dropout regulator controllers. The controllers provide the power for the system AGTL bus Termination Voltage, Chipset, and clock circuitry. An adjustable controller with a 1.2V reference is available, while two selectable outputs are provided for the VTT (1.25 V or 1.5V, SC1112) or (1.2V or 1.5V, SC1112A) and the AGP (1.5V or 3.3V). The SC1112 low dropout regulators are designed to track the 3.3V power supply as the VTTIN supply is cycled On and Off. A latched short circuit protection is also available for the VTT output. Other features include an integrated charge pump that provides adequate gate drives for the external Mosfets, and a capacitive programable delay for the power good signal. SC1112 .eatures K Triple linear controllers K Selectable and Adjustable Output Voltages K LDOs track input voltage within 200mV (.unction of the Mosfets used) until regulation K Integrated Charge Pump K Programmable Power Good delay Signal K Latched Over Current Protection (VTT) Applications K Pentium® III Motherboards K Triple power supplies Typical Application Circuit +3.3V VTT +5V STBY 1K R1 POWER GOOD C6 330u Q2 5VSTBY ADJGATE C1 10u SC1112/A GND AGPGATE AGPSEN VTTGATE VTTSEN AGPSEL VTTSEL VTTIN C3 0.1u Q3 C14 330u AGP Q1 C2 C18 330u C16 330u C17 0.1u VTT C19 330u C8 330u C9 0.1u ADJ RA ADJSEN 0.1u C11 CAPCAP+ 1u C10 ...