Description

The MAX1955/MAX1956 are dual-output, fixed-frequency, voltage-mode, pulse-width modulated (PWM) step-down controllers with 0.5% output accuracy. Each controller switches at a constant 600kHz and is 180° out-of-phase with the other controller, reducing input ripple current and the number of input capacitors.An on-chip bias supply generates a 5V gate drive to deliver up to 25A output current per phase with low-cost N-channel MOSFETs at up to 93% efficiency. Lossless adjustable current limit eliminates expensive current-sense resistors and improves efficiency. Foldback current limit reduces power dissipation during short-circuit conditions and handles transient overloads better than controllers using hiccup-mode short-circuit protection.Output voltage margining shifts output voltage by±4% from the nominal value to simplify system test. Outputs also can be powered up and down in selectable sequences to meet core and logic supply-rail requirements.The MAX1955/MAX1956 are available in a 28-lead thin QFN package with exposed pad.ApplicationsDSP, ASIC, µP, and FPGA SuppliesServersTelecom and Network EquipmentWireless Base Stations