MAX8745A Datasheet | Maxim Integrated

Description Features o o o o o o o o o o o o o o Fixed-Frequency, Current-Mode Control 40/60 Optimal Interleaving Internal BST Switches Internal 5V, 100m A Linear Regulator Auxiliary Linear-Regulator Driver (12V or Adjustable Down to 1V) Dual Mode™ Feedback- 3.3V/5V Fixed or Adjustable Output Voltages 200k Hz/300k Hz/500k Hz 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 MAX8744A/MAX8745A PGOODA LDO5 DL3 DL5 LX3 The MAX8744A/MAX8745A are available in a 32-pin, 5mm x 5mm, thin QFN package. The exposed backside pad improves thermal characteristics for demanding linear keep-alive applications. 24 DH3 25 BST3 26 PGOOD3 27 CSL3 28 CSH3 29 FB3 30 FBA 31 OUTA 32 1 ONA + 17 16 15 14 13 DH5 BST5 PGOOD5 CSL5 CSH5 FB5 SKIP FSEL Applications Main Power Supplies 2 to 4 Li+ Cell Battery-Powered Devices Notebook and Subnotebook puters PDAs and Mobile municators MAX8744A MAX8745A LX5 TOP VIEW PGND The MAX8744A/MAX8745A 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, pared to 180° out-of-phase regulators where the duty-cycle overlap occurs when the input drops below 10V. Output current sensing provides peak current-limit protection, using either an accurate sense resistor or using lossless inductor DCR current sensing. A low-noise mode maintains high light-load efficiency while keeping the switching frequency out of the audible range. An internal, fixed 5V, 100m A...