RT8889D Datasheet, PDF (1/44 Pages) Richtek Technology Corporation – 3-Phase PWM Controller

®
RT8889D
3-Phase PWM Controller with Triple Integrated Drivers for
VR12.5 CPU Core Power Supply
General Description
The RT8889D is a three phase CPU power controller with
triple integrated drivers for VR12.5 compliant. The
RT8889D adopts G-NAVP^TM (Green Native AVP) which is
Richtek's proprietary topology derived from finite DC gain
of EA amplifier with current mode control, making it an
easy setting the droop to meet all Intel CPU requirements
of AVP (Adaptive Voltage Positioning). Based on the G-
NAVP^TM topology, the RT8889D also features a quick
response mechanism for optimized AVP performance
during load transient. The RT8889D supports mode
transition function with various operating states. A Serial
VID (SVID) interface is built in the RT8889D to
communicate with Intel VR12.5 compliant CPU. The
RT8889D supports VID on-the-fly function with three
different slew rates : Fast, Slow and Decay. By utilizing
the G-NAVP^TM topology, the operating frequency of the
RT8889D varies with VID, load current and input voltage
to further enhance the efficiency even in CCM. Besides
G-NAVP^TM, the CCRCOT (Constant Current Ripple
Constant On Time) technology provides superior output
voltage ripple over the entire input/output range. The built-
in high accuracy DAC converts the SVID code ranging
from 0.5V to 3.04V with 10mV per step. The RT8889D
integrates a high accuracy ADC for platform setting
functions, such as no-load offset and over current
protection level. It also features complete fault protection
functions including Over Voltage (OV), Under Voltage (UV),
Negative Voltage (NV), Over Current (OC) and Under
Voltage Lockout (UVLO). The RT8889D is available in a
WQFN-40L 5x5 small foot print package.
Features
 Intel VR12.5 Serial VID Interface Compatible Power
Management States
 3/2/1 Phase PWM Controller with Triple Integrated
Driver
 G-NAVP^TM Topology
 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
Single Phase
 Fast transient Response
 VR Ready Indicator
 Thermal Throttling
 Current Monitor Output
 OVP, UVP, OCP, UVLO
 External No-Load Offset Setting
 DVID Enhancement
 Small 40-Lead WQFN Package
Applications
 VR12.5 Intel Core Supply
 Notebook/Desktop Computer/Servers Multi-phase CPU
Core Supply
 AVP Step-Down Converters
Simplified Application Circuit
To PCH
To CPU
RT8889D
VR_RDY PHASE1
VR_HOT
VCLK
PHASE2
VDIO
ALERT PHASE3
MOSFET
MOSFET
MOSFET
V_CORE
Copyright ©2015 Richtek Technology Corporation. All rights reserved.
DS8889D-00 April 2015
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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