MAX17009

• Dual Output, Fast-Response Interleaved Fixed Frequency
• AMD Mobile SVI-Compliant Serial Interface
• Separate or Combinable Outputs Detected at Power-Up
• Reference Buffer Output
• Dynamic Phase Selection Optimizes Active/Sleep Efficiency
• Transient Phase Repeat Reduces Output Capacitance
• Active Voltage Positioning with Adjustable Gain
• High Speed, Accuracy, and Efficiency
• Low-Bulk Output Capacitor Count
• 7V to 24V Input-Voltage Range
• 0 to 1.550V Output-Voltage Range (7-Bit On-Board DAC)
• 36A Load-Current Capability (18A Each Phase)
• Accurate Current Balance and Current Limit
• 300kHz Switching Frequency (per Phase)
• Power-Good (PWRGD) and Thermal-Fault (Active-Low VRHOT) Output Indicators
• System Power-OK (PGD_IN) Input
• Output Overvoltage and Undervoltage Fault Protection
• 40-Pin Thin QFN Package (5mm x 5mm)
• Fully Assembled and Tested

The MAX17009 evaluation kit (EV kit) demonstrates the high-power, dynamically adjustable, dual-phase notebook CPU application circuit for AMD® mobile serial VID interface (SVI) CPU core supplies. This DC-DC converter steps down high-voltage batteries and/or AC adapters, generating a precision, low-voltage CPU core. The MAX17009 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 MAX17009 EV kit consists of the MAX17009 dual-phase, interleaved fixed-frequency step-down controller, configured for separate mode operation, and a reference buffer. The switching regulators (SMPSs) provide power to two independent CPU cores, while the reference buffer output (NBV_BUF) sets the voltage regulation level for a north bridge (NB) regulator, completing the total CPU cores and NB power requirements.

Output voltages are dynamically changed through a 2-wire serial interface, allowing the SMPS and the NBV_BUF to be individually programmed to different voltages. A programmable slew-rate controller enables controlled upward transitions between VID codes for the switching regulators, while the slew rate for the reference buffer is set by an external capacitor.

Soft-start limits the inrush current, and soft-shutdown brings the output voltage back down to zero without any negative ring. The MAX17009 EV kit includes active voltage positioning with adjustable gain, reducing power dissipation and bulk output capacitance requirements. The MAX17009 includes latched output undervoltage fault, overvoltage fault protection, and thermal-overload protection. It also includes a voltage-regulator power-good (PWRGD) output.

This fully assembled and tested printed circuit board (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 delivers up to 18A output current for a total of 36A. The EV kit operates at 300kHz switching frequency (per phase) and has superior line- and load-transient response. The EV kit also includes Windows® 2000/XP-compatible software, which provides a simple graphical user interface (GUI) for exercising the features of the MAX17009.

Applications

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