The MAX8716/MAX8717/MAX8756/MAX8757 are dual, step-down, interleaved, fixed-frequency, switch-mode power-supply (SMPS) controllers with synchronous rectification. The MAX8716/MAX8717/MAX8756/MAX8757 are intended for main (5V/3.3V) power generation, while the MAX8756 is optimized for I/O power rails 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 in 5V/3.3V applications, compared to 180° out-of-phase regulators where the duty-cycle overlap occurs when the input drops below 10V.Accurate output current limit is achieved using a sense resistor. Alternatively, power dissipation can be reduced using lossless inductor current sensing. Independent ON/OFF controls and power-good signals allow flexible power sequencing. Soft-start reduces inrush current, while soft-stop gradually ramps the output voltage down preventing negative voltage dips.A low-noise mode maintains high light-load efficiency while keeping the switching frequency out of the audible range.The MAX8716 is available in a 24-pin thin QFN package, and the MAX8717/MAX8756/MAX8757 are available in a 28-pin thin QFN package.Applications2 to 4 Li+ Cell Battery-Powered DevicesMain or I/O Power SuppliesNotebook and Subnotebook ComputersPDAs and Mobile Communicators