AMD Mobile Serial VID Dual-Phase Fixed-Frequency Controller

The MAX17009 is a two-phase, step-down interleaved, fixed-frequency controller for AMD's serial VID interface (SVI) CPU core supplies. Power-on detection of the CPU configures the MAX17009 as two independent single-phase regulators for a dual CPU core application, or one high-current, dual-phase, combined-output regulator for a unified core application. A reference buffer output (NBVBUF) sets the voltage-regulation level for a North Bridge (NB) regulator, completing the total CPU cores and NB power requirements.

The MAX17009 is fully AMD SVI compliant. Output voltages are dynamically changed through a 2-wire serial interface, allowing the switching regulator and the reference buffer to be individually programmed to different voltages. A programmable slew-rate controller enables controlled transitions between VID codes, soft-start limits the inrush current, and soft-shutdown brings the output voltage back down to zero without any negative ring.

Transient phase repeat improves the response of the fixed-frequency architecture. Independently programmable AC and DC droop and selectable offset improve stability and reduce the total output-capacitance requirement. A thermistor-based temperature sensor allows for a programmable thermal-fault output (active-low VRHOT). The MAX17009 includes thermal-fault protection, undervoltage protection (UVP), and selectable output overvoltage protection (OVP). When any of these protection features detect a fault, the controller shuts down. True differential current sensing improves current limit, load-line accuracy, and current balance when operating in combined mode. The MAX17009 has an adjustable switching frequency, allowing 100kHz to 1.2MHz per-phase operation.

Applications

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

* Dual-Output, Fixed-Frequency, Core Supply Controller

* Separate or Combinable Outputs Detected at Power-Up

* Reference Buffer Output for NB Controller

* ±0.4% VOUT Accuracy Over Line, Load, and Temperature

* AMD SVI-Compliant Serial Interface

* 7-Bit On-Board DAC: 0 to +1.550V Output Adjust Range

* Dynamic Phase Selection Optimizes Active/Sleep Efficiency

* Transient Phase Repeat Reduces Output Capacitance

* True Out-of-Phase Operation Reduces Input Capacitance

* Integrated Boost Switches

* Programmable AC and DC Droop

* Programmable 100kHz to 1.2MHz Switching Frequency

* Accurate Current Balance and Current Limit

* Adjustable Slew-Rate Control

* Power-Good (PWRGD) and Thermal-Fault (Active-Low VRHOT) Outputs

* System Power-OK (PGDIN) Input

* Drives Large Synchronous-Rectifier MOSFETs

* 4V to 26V Battery Input-Voltage Range

* Overvoltage, Undervoltage, and Thermal-Fault Protection

* Power Sequencing and Timing

* Soft-Startup and Soft-Shutdown

* < 1µA Typical Shutdown Current