General Description

The MAX8743 is a dual pulse-width modulation (PWM) controller configured for step-down (buck) topologies that provides the high efficiency, excellent transient response, and high DC output accuracy necessary for stepping down high-voltage batteries to generate lowvoltage chipset and RAM power supplies in notebook computers. The CS_ inputs can be used with low-side sense resistors to provide accurate current limits or can be connected to LX_, using low-side MOSFETs as current-sense elements. High output impedance in shutdown eliminates negative output voltages, saving the cost of a Schottky diode at the output.

Features

♦ Ultra-High Efficiency

♦ Accurate Current-Limit Option

♦ Quick-PWM™ with 100ns Load-Step Response

♦ 1 VOUT Accuracy over Line and Load

♦ High Output Impedance in Shutdown

♦ Dual Mode™ Fixed 1.8V/1.5V/Adj or 2.5V/Adj Outputs

♦ Adjustable 1V to 5.5V Output Range

♦ 2V to 28V Battery Input Range

♦ 200kHz/300kHz/420kHz/540kHz Nominal Switching Frequency

♦ Adjustable Overvoltage Protection

♦ 1.7ms Digital Soft-Start

♦ Drives Large Synchronous-Rectifier FETs

♦ Power-Good Window Comparator

♦ 2V ±1 Reference Output

Applications

    Notebook Computers

    CPU Core Supplies

    Chipset/RAM Supplies as Low as 1V

    1.8V and 2.5V I/O Supplies