General Description

The MAX8744A/MAX8745A are dual step-down, switch mode, 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 rip ple 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.

特性 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 (MAX8744A 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