MAX8707

19-3360; Rev 0; 8/04 Multiphase, Fixed-Frequency Controller for AMD Hammer CPU Core Power Supplies General Description The MAX8707 is a multiphase (3-/4-phase), interleaved, fixed-frequency, step-down controller for AMD Hammer CPU core supplies. Interleaved multiphase operation reduces the input ripple current and output voltage ripple while easing component selection and layout placement. The MAX8707 includes active voltage positioning with adjustable gain and offset, reducing power dissipation and bulk output-capacitance requirements. The MAX8707 is intended for two different notebook CPU core applications: stepping down the battery directly or stepping down the +5V system supply to create the core voltage. The single-stage conversion method allows these devices to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, 2-stage conversion (stepping down the +5V system supply instead of the battery) at higher switching frequency provides the minimum possible physical size. The MAX8707 features dedicated differential currentsense inputs for each phase and includes a fifth pair of current-sense inputs to provide an accurate voltagepositioning slope and average current-limit protection using a single current-sense resistor. The MAX8707 also has two dedicated inputs that provide differential remote voltage sensing. The MAX8707 provides an analog input for setting the suspend voltage and a slew-rate controller for transitions between VID cod...