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