General Description
The MAX1549 dual pulse-width modulation (PWM) stepdown controller provides the high efficiency, excellent transient response, and high DC-output accuracy necessary for generating low-voltage chipset and RAM power supplies in notebook computers. The controller employs a fixed-frequency, current-mode PWM architecture that does not require complex compensation. The MAX1549 also interleaves the dual step-down regulators, minimizing the input capacitor requirements.

Features
♦ Interleaved, Fixed-Frequency, Current-Mode Control Architecture
♦ 1% VOUT Accuracy Over Line and Load
♦ Main Output (OUT1)
    0.5V to 2.0V Adjustable Output
    External Reference Input for Dynamically
    Selectable Output Voltages
    Four Digitally Selectable Output Voltages
    Power-Good and Fault Blanking During
    Transitions
♦ Second Output (OUT2) 2.5V/1.8V Fixed or 0.5V to 2.7V Adjustable Output
♦ Accurate Differential Current-Sense Inputs
♦ 100kHz/200kHz/300kHz/400kHz Selectable Switching Frequency
♦ Output Overvoltage/Undervoltage Protection
♦ Soft-Start and Soft-Shutdown
♦ Drives Large Synchronous-Rectifier FETs
♦ 2V ±0.6% Reference Output
♦ Separate Enable Inputs with Accurate Threshold Voltages
♦ Separate Power-Good Window Comparators

Applications
    Notebook Computers
    Dynamically Adjustable Chipset Supplies
    Video/GPU Core Supplies
    DDR Memory Termination
    CPU Core or VCC Supplies
    Fixed Chipset/RAM Supplies
    Active Termination Buses