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