General Description
The MAX8744/MAX8745 are dual step-down, switchmode, power-supply (SMPS) controllers with synchronous rectification, intended for main 5V/3.3V power generation in battery-powered systems. Fixed-frequency operation with optimal interleaving minimizes input ripple current from the lowest input voltages up to the 26V maximum input. Optimal 40/60 interleaving allows the input voltage to go down to 8.3V before duty-cycle overlap occurs, compared to 180° out-of-phase regulators where the duty-cycle overlap occurs when the input drops below 10V.

Features
♦ Fixed-Frequency, Current-Mode Control
♦ 40/60 Optimal Interleaving
♦ Internal BST Switches
♦ Internal 5V, 100mA Linear Regulator
♦ Auxiliary Linear-Regulator Driver (12V or Adjustable Down to 1V)
♦ Dual Mode™ Feedback—3.3V/5V Fixed or Adjustable Output Voltages
♦ 200kHz/300kHz/500kHz Switching Frequency
♦ Undervoltage and Thermal-Fault Protection
♦ Overvoltage-Fault Protection (MAX8744 Only)
♦ 6V to 26V Input Range
♦ 2V ±0.75% Reference Output
♦ Independent Enable Inputs and Power-Good Outputs
♦ Soft-Start and Soft-Shutdown (Voltage Ramp)
♦ 8µA (typ) Shutdown Current

Applications
    Main Power Supplies
    2 to 4 Li+ Cell Battery-Powered Devices
    Notebook and Subnotebook Computers
    PDAs and Mobile Communicators