General Description
The MAX1638 is an ultra-high-performance, step-down DC-DC controller for CPU power in high-end computer systems. Designed for demanding applications in which output voltage precision and good transient response are critical for proper operation, it delivers over 35A from 1.3V to 3.5V with ±1% total accuracy from a +5V ±10% supply. Excellent dynamic response corrects output transients caused by the latest dynamically clocked CPUs. This controller achieves over 90% efficiency by using synchronous rectification. Flying-capacitor bootstrap circuitry drives inexpensive, external N-channel MOSFETs.

Features
♦ Better than ±1% Output Accuracy Over Line and Load
♦ Greater than 90% Efficiency Using N-Channel MOSFETs
♦ Pin-Selected High Switching Frequency (300kHz, 600kHz, or 1MHz)
♦ Over 35A Output Current
♦ Digitally Programmable Output from 1.3V to 3.5V
♦ Current-Mode Control for Fast Transient Response and Cycle-by-Cycle Current-Limit Protection
♦ Short-Circuit Protection with Foldback Current Limiting
♦ Glitch-Catcher Circuit for Fast Load-Transient Response
♦ Crowbar Overvoltage Protection
♦ Power-Good (PWROK) Output
♦ Digital Soft-Start
♦ High-Current (2A) Drive Outputs
♦ Complies with Intel VRM 8.2 Specification

Applications
    Pentium Pro™, Pentium II™, PowerPC™, Alpha™, and K6™ Systems
    Workstations
    Desktop Computers
    LAN Servers
    GTL Bus Termination