General Description

The MAX8550A integrates a synchronous-buck PWM controller to generate VDDQ, a sourcing and sinking LDO linear regulator to generate VTT, and a 10mA reference output buffer to generate VTTR. The buck controller drives two external n-channel MOSFETs to generate output voltages down to 0.7V from a 2V to 28V input with output currents up to 15A. The LDO can sink or source up to 1.5A continuous and 3A peak current. Both the LDO output and the 10mA reference buffer output can be made to track the REFIN voltage. These features make the MAX8550A ideally suited for DDR memory applications in desktops, notebooks, and graphic cards.

Features

Buck Controller

♦ Quick-PWM with 100ns Load-Step Response

♦ Up to 95 Efficiency

♦ 2V to 28V Input Voltage Range

♦ 1.8V/2.5V Fixed or 0.7V to 5.5V Adjustable Output

♦ Up to 600kHz Selectable Switching Frequency

♦ Programmable Current Limit with Foldback Capability

♦ 1.7ms Digital Soft-Start

♦ Independent Shutdown and Standby Controls

♦ Overvoltage/Undervoltage-Protection Option

♦ Power-Good Window Comparator LDO Section

♦ Fully Integrated VTT and VTTR Capability

♦ VTT Has ±3A Sourcing/Sinking Capability

♦ VTT and VTTR Outputs Track VREFIN / 2

♦ All-Ceramic Output-Capacitor Designs

♦ 1.0V to 2.8V Input Voltage Range

♦ Power-Good Window Comparator

Applications

    DDR I and DDR II Memory Power Supplies

    Desktop Computers

    Notebooks and Desknotes

    Graphic Cards

    Game Consoles

    RAID

    Networking