Advanced 4/3-Phase PWM Controller for CPU Core Power


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The RT8867A is an advanced 4/3-phase synchronous buck controller with 3 integrated MOSFET drivers. It integrates an 8-bit DAC that supports Intel VR11.x CPUs power application.

The IC adopts state-of-the-art dynamic phase control capability by PS1/2/3 pins and achieves high efficiency over a wide load range. It uses lossless RDS(ON) current sensing to achieve phase current balance. Other features include adjustable operating frequency, adjustable soft-start, short circuit protection, adjustable over current protection, over voltage protection, under voltage protection, power good indication, VR_HOT indication and VR_SHDN indication.

The RT8867A is available in a small footprint with WQFN-48L 6x6 package.


  • Desktop CPU Core Power
  • Middle/High End Graphic Cards
  • Low Voltage, High Current DC/ DC Converters
  • Motherboards
Key Spec.
Status Active
VID Table Support VR11.0;VR11.1
Number of Phases 4
Vcc (typ) (V) 12
Vin (min) (V) 10.8
Vin (max) (V) 13.2
Accuracy (Vout>=1V) (+/- %) 0.5
Freq (typ) (kHz) 300
Built-in DAC Generator Yes
Number of MOSFET Drivers 3
Features Adjustable Frequency;Adjustable Soft-Start;Built-in Bootstrap Switch;DCR Current Sense;Droop Control;Enable Input;OCP;OVP;Power Good;SCP;UVP;Voltage Mode Control
Package Type WQFN6x6-48
  • 12V Power Supply Voltage
  • 4/3-Phase Power Conversion
  • Integrated 3 MOSFET Drivers with Internal Bootstrap Diode
  • Dynamic Phase Control Capability
  • 8-bit DAC Supports Intel VR11.x CPUs
  • Lossless RDS(ON) Current Sensing for Current Balance
  • Adjustable Frequency : 50kHz to 1MHz
  • Adjustable Over Current Protection
  • Adjustable Soft-Start
  • VR_RDY, VR_HOT and VR_SHDN Indications
  • Small 48-Lead WQFN Package
  • RoHS Compliant and Halogen Free
TitleLast UpdateShareDownload
Advanced 4/3-Phase PWM Controller for CPU Core Power2011/05/19