The RT8859M is a VR12/IMVP7 compliant CPU power controller which includes two voltage rails : a 4/3/2/1 phase synchronous buck controller, the CORE VR, and a single phase buck controller, the AXG VR. The RT8859M adopts G-NAVPTM (Green Native AVP), which is Richtek's proprietary topology derived from finite DC gain compensator with current mode control, making it an easy setting PWM controller, meeting all Intel CPU requirements of AVP (Active Voltage Positioning). Based on the G-NAVPTM topology, the RT8859M also features a quick response mechanism for optimized AVP performance during load transient. The RT8859M supports mode transition function with various operating states. A serial VID (SVID) interface is built in the RT8859M to communicate with Intel VR12/IMVP7 compliant CPU. The RT8859M supports VID on-the-fly function with three different slew rates: Fast, Slow and Decay. By utilizing the G-NAVPTM topology, the operating frequency of the RT8859M varies with VID, load and input voltage to further enhance the efficiency even in CCM. The built-in high accuracy DAC converts the SVID code ranging from 0.25V to 1.52V with 5mV per step. The RT8859M integrates a high accuracy ADC for platform setting functions, such as no-load offset or over-current level. The RT8859M provides VR ready output signals of both CORE VR and AXG VR. It also features complete fault protection functions including over voltage, under voltage, negative voltage, over current and under voltage lockout. The RT8859M is available in a WQFN-56L 7x7 small foot print package.


  • VR12 / IMVP7 Intel Core Supply
  • Notebook/ Desktop Computer/ Servers Multi-phase CPU Core Supply
  • AVP Step-Down Converter
Key Spec.
Status Active
VID Table Support VR12
Number of Phases 1;4
Vcc (typ) (V) 5
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 0
Features Adjustable Current Limit;Adjustable Frequency;Cycle-by-Cycle Current Limit;DCR Current Sense;Diode Emulation Mode;Droop Control;Enable Input;Fast Transient Response;G-NAVP Control;OVP;Power Good;SCP;UVP
Package Type WQFN7x7-56
  • 4/3/2/1 + 1 Phase PWM Controller
  • G-NAVPTM Topology
  • Serial VID Interface
  • 0.5% DAC Accuracy
  • Differential Remote Voltage Sensing
  • Built-in ADC for Platform Programming
  • Accurate Current Balance
  • System Thermal Compensated AVP
  • Diode Emulation Mode at Light Load Condition for Multiple and Single Phase
  • Fast Transient Response
  • VR12 / IMVP7 Compatible Power Management States
  • VR Ready Indicator
  • Thermal Throttling
  • Current Monitor Output
  • Switching Frequency up to 1MHz per Phase
  • Slew Rate Setting/Address Flip Function
  • External No-Load Offset Setting for both Rails
  • DVID Improvement
  • Small 56-Lead WQFN Package
  • RoHS Compliant and Halogen Free
TitleLast UpdateDownload
Multi-Phase PWM Controller for CPU Core Power Supply2012/04/19