General Description

The MAX8597/MAX8598/MAX8599 voltage-mode PWM step-down controllers are designed to operate from a 4.5V to 28V input supply and generate output voltages down to 0.6V. A proprietary switching algorithm stretches the duty cycle to >99.5 for low-dropout design. Unlike conventional step-down regulators using a p-channel high-side MOSFET to achieve high duty cycle, the MAX8597/MAX8598/MAX8599 drive n-channel MOSFETs resulting in high efficiency and high-currentcapability designs.

Features

♦ Low Dropout with >99.5 Duty Cycle

♦ Lossless High-Side Current Limit

♦ Wide 4.5V to 28V Input Range

♦ Dynamic Output Voltage Adjustment with Adjustable Offset (MAX8597)

♦ Remote Voltage Sensing for Both Positive and Negative Rails (MAX8597)

♦ Tracking Output Through REFIN (MAX8597)

♦ Adjustable Switching Frequency from 200kHz to 1.4MHz

♦ Adjustable Soft-Start

♦ Prebias Startup

♦ Enable and Power-OK (MAX8598/MAX8599) for Flexible Sequencing

♦ 25MHz Error Amplifier

♦ Adjustable Hiccup Current Limit for Output Short-Circuit Protection

♦ Output Overvoltage Protection (MAX8599)

♦ Small, Low-Profile Thin QFN Package

Applications

    Nonisolated Power Modules

    Variable-Speed DC Fan Power Supplies (MAX8597)

    Tracking Power Supplies (MAX8597)

    Chipset Power Supplies