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Dual Output 3-Phase + 2-Phase PWM Controller For CPU and GPU Core Power Supply

RT8885A

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The RT8885A is a dual output 3-phase + 2-phase PWM controller with 3 integrated MOSFET gate drivers and a single SVID interface for CPU and GPU core power supply. This part complies with Intel VR12/IMVP7 Pulse Width Modulation Specification. The RT8885A adopts G-NAVPTM (Green-Native AVP), which is a Richtek proprietary topology derived from finite DC gain compensator in constant on-time control mode. G-NAVPTM makes this part an easy-setting PWM controller to meet all Intel mobile CPU/GPU AVP (Active Voltage Positioning) requirements. The RT8885A uses SVID interface to control an internal 8-bit DAC for output voltage programming. The built-in high accuracy DAC converts the VID code to a reference voltage ranging from 0V to 1.52V with 5mV step voltage. The system accuracy of the controller reaches 0.8%. Each output channel of the RT8885A can operate in multi-phase continuous conduction mode or in single-phase diode emulation mode to reach a maximum of 90% efficiency in different load conditions. The droop function (load line) is selectable and the load line is easily programmed by setting the DC gain of the error amplifier. With proper compensation, the load transient response can achieve optimized AVP performance. The output voltage transition slew rate is programmed via the SVID interface. The RT8885A supports inductor DCR and sense-resistor current sensing. This device provides power good indication, current monitor, thermal monitor and thermal throttling output signals for IMVP7 CPU and GPU core. This part also provides complete fault protection functions including over voltage, under voltage, negative voltage, over current, thermal shutdown and under voltage lockout.

Applications

  • IMVP7 Intel CPU/CPU Core Power Supply
  • Laptop Computer
  • AVP Step-Down Converter
Key Spec.
RT8885A
Status Active
VID Table Support VR12
Number of Phases 2;3
Vcc (typ) (V) 5
Vin (min) (V) 6
Vin (max) (V) 24
Accuracy (Vout>=1V) (+/- %) 0.5
Freq (typ) (kHz) 300
Built-in DAC Generator Yes
Number of MOSFET Drivers 1;2
Features Adjustable Frequency;DCR Current Sense;Droop Control;Enable Input;OCP;OVP;Power Good
Package Type WQFN7x7-56
Features
  • Dual Output : 3-Phase (CORE) + 2-Phase (GFX)
  • Integrated MOSFET Drivers : 2 (CORE) + 1 (GFX)
  • VR12/IMVP7 PWM Specification Compliant
  • Serial VID Interface
  • G-NAVPTM Topology
  • Fast Line/Load Transient Response
  • Quick Response for Load Transient
  • 0.5% DAC Accuracy
  • 0.8% System Accuracy
  • Accurate Current Balance
  • Selectable Droop Function
  • Selectable Forced DEM Operation
  • Built-in ADC for Platform Programming
  • Power Good Indicator
  • Current Monitor Output
  • Thermal Monitor
  • Thermal Throttling Indicator VRHOT
  • Phase Shedding in PS1
  • Phase Shedding and Diode Emulation in PS2
  • Differential Remote Output Voltage Sense
  • Lossless Inductor DCR Current Sense
  • Switching Frequency up to 1MHz per Phase
  • OVP, UVP, NVP, OCP, OTP, UVLO
  • 56-Lead WQFN Package
  • RoHS Compliant and Halogen Free
Technical Documents
TitleLast UpdateShareDownload
Richtek Vcore Product Selection List for Intel and AMD platforms [May, 2017]2018/11/15
Introduction to Richtek VCORE Solutions2017/10/18
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