The LM2638 provides a comprehensive embedded power supply solution for motherboards hosting high performance MPUs such as PentiumTM II, M IITM, K6TM-2 and other similar high performance MPUs. The LM2638 incorporates a 5-bit programmable, synchronous buck switching controller and two high-speed linear regulator controllers in a 24-pin SO package. In a typical application, the switching controller supplies the MPU core, and the linear regulator controllers supply the GTL+ bus and the clock or graphics chip core. A charge pump pin helps provide the necessary voltage to power the linear sections when 12V is shut off during system standby such as STR mode.