Dual-Phase, Quick-PWM Controller for AMD Mobile Turion 64 CPU Core Power Supplies

The MAX8760 is a dual-phase, Quick-PWM™, stepdown controller for 6-bit VID AMD Mobile Turion™ 64 CPU core supplies. Dual-phase operation reduces input ripple current requirements and output voltage ripple while easing component selection and layout difficulties. The Quick-PWM control scheme provides instantaneous response to fast-load current steps. The MAX8760 includes active voltage positioning with adjustable gain and offset, reducing power dissipation and bulk output capacitance requirements.

The MAX8760 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 this device to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, two-stage conversion (stepping down the 5V system supply instead of the battery) at a higher switching frequency provides the minimum possible physical size.

The MAX8760 complies with AMD's desktop and mobile CPU specifications. The switching regulator features soft-start and power-up sequencing, and soft-shutdown. The MAX8760 also features independent four-level logic inputs for setting the suspend voltage (S0, S1).

The MAX8760 includes output undervoltage protection, thermal protection, and voltage regulator power-OK (VROK) output. When any of these protection features detect a fault, the controller shuts down.

The MAX8760 is available in a low-profile, 40-pin 6mm x 6mm thin QFN package. For other CPU platforms, refer to the pin-to-pin compatible MAX1544 data sheets.

Applications

* 6-Bit VID AMD Mobile Turion 64 CPU * Multiphase CPU Core Supplies * Servers/Desktop Computers * Voltage-Positioned Step-Down Converters

* Dual-Phase, Quick-PWM Controller

* ±0.75% VOUT Accuracy Over Line, Load, and Temperature (1.3V)

* Active Voltage Positioning with Adjustable Gain and Offset

* 6-Bit On-Board DAC: 0.375V to 1.55V Output Adjust Range

* Selectable 100kHz/200kHz/300kHz/550kHz Switching Frequency

* 4V to 28V Battery Input Voltage Range

* Adjustable Slew-Rate Control

* Drives Large Synchronous Rectifier MOSFETs

* Undervoltage and Thermal-Fault Protection

* Power Sequencing and Timing

* Selectable Suspend Voltage

* Soft-Start and Soft-Shutdown

* Selectable Single- or Dual-Phase Pulse Skipping