LM2637

LM2637 Motherboard Power Supply Solution with a 5-Bit Programmable Switching Controller and Two Linear Regulator Controllers October 1998 LM2637 Motherboard Power Supply Solution with a 5-Bit Programmable Switching Controller and Two Linear Regulator Controllers General Description The LM2637 provides a comprehensive embedded power supply solution for motherboards hosting high performance MPUs such as M II™, Pentium™ II, K6-2 and other similar high performance MPUs. The LM2637 incorporates a 5-bit programmable, synchronous buck switching controller and two high-speed linear regulator controllers in a 24-pin SO package. Both linear controllers have under voltage latch-off. Features n Provides 3 regulated voltages n Power Good flag and output enable n Under-voltage latch-off Switching Section n Synchronous rectification n 5-bit DAC programmable from 3.5V to 1.3V n Typical 1% DAC tolerance n Switching frequency: 50 kHz to 1 MHz n Two levels of over-voltage protection n Two methods of over-current protection n Adaptive non-overlapping FET gate drives n Soft start without external capacitor Linear Section n N-FET and NPN driving capability n Ultra fast response speed n Output voltages default to 1.5V and 2.5V yet adjustable Switching Section — The switching regulator controller features a 5-bit programmable DAC, over-current and over-voltage protection, under-voltage latch-off, a power good signal, and output enable. The 5-bit DAC has a typical tolerance of 1%. There are two u...