MAX17480

• Dual/Triple-Output, Fixed-Frequency Controller
• AMD Mobile SVI-Compliant Serial Interface
• 0 to 1.550V Output-Voltage Range (7-Bit On-Board DAC)
• Core SMPS
  • Split or Combinable Outputs Detected at Power-Up
  • True Out-of-Phase Operation Reduces Input Capacitance
  • Transient Phase Repeat Reduces Output Capacitance
  • Dynamic Phase Selection Optimizes Active/Sleep Efficiency
  • Programmable AC and DC Droop
  • 7V to 24V Input-Voltage Range
  • 36A Load-Current Capability (18A Each Phase)
  • Accurate Current Balance and Current Limit
  • 300kHz Switching Frequency (Per Phase)
  • Output Overvoltage Fault Protection
• NB SMPS
  • 4A Load-Current Capability for Northbridge Core
  • 600kHz Switching Frequency for Northbridge
• Power-Good (PWRGD) and Thermal-Fault (Active-Low VRHOT) Output Indicators
• System Power-OK (PGD_IN) Input
• Undervoltage Fault Protection
• 40-Pin Thin QFN Package (5mm x 5mm)
• Lead(Pb)-Free and RoHS Compliant
• Fully Assembled and Tested

The MAX17480 evaluation kit (EV kit) demonstrates the high-power, triple-output notebook CPU application circuit for the AMD® mobile serial VID interface (SVI) CPU core supplies. This DC-DC converter steps down high-voltage batteries and/or AC adapters, generating precision, low-voltage CPU cores. The MAX17480 EV kit meets the AMD mobile SVI CPU’s transient voltage specification, power-good signaling, voltage-regulator thermal monitoring (active-low VRHOT), and power-good output (PWRGD). The MAX17480 EV kit consists of one dual-phase high-current switched-mode power supply (SMPS) for the CPU core (VCORE0) and one 4A internal switch SMPS for the northbridge (NB) core. The two CPU core SMPSs run 180° out-of-phase for true interleaved operation, minimizing input capacitance.

Output voltages are dynamically changed through a 2-wire serial interface, allowing the switching regulators to be individually programmed to different voltages. A programmable slew-rate controller enables controlled transitions between VID codes. SVI also allows each regulator to be individually set into a low-power pulse-skipping state.

Soft-start limits the inrush current, and passive shutdown discharges the output voltage back down to zero without any negative ring. The MAX17480 EV kit includes active voltage positioning with adjustable gain, reducing power dissipation and bulk output capacitance requirements. The MAX17480 includes latched output undervoltage fault protection, overvoltage fault protection for the CPU cores, and thermal-overload protection. It also includes a voltage-regulator power-good (PWRGD) output.

This fully assembled and tested PCB provides a digitally adjustable 0 to 1.550V output-voltage range (7-bit on-board DAC) from a 7V to 24V battery input range. Each phase of the core current SMPS operates at 300kHz switching frequency and delivers up to 18A output current for a total of 36A. The 4A internal switch SMPS operates at 600kHz switching frequency and delivers up to 4A. The EV kit has superior line- and load-transient response. The EV kit also includes Windows® 2000-, Windows XP®-, and Windows Vista®-compatible software that provides a simple graphical user interface (GUI) for exercising the features of the MAX17480.

Applications

• Mobile AMD SVI Core Supplies
• Multiphase CPU Core Supplies
• Notebook/Desktop Computers
• Voltage-Positioned, Step-Down Converters