®
RT8876A
Dual Channel PWM Controller with 3/2/1 Phase for CORE VR
and Single Phase for AXG VR
General Description
Features
z VR12/IMVP7 Compatible Power Management
z 3/2/1 Phase for CORE VR and Single Phase for AXG
VR
The RT8876A is a VR12/IMVP7 compliant CPU power
controller which includes two channels : a 3/2/1 phase
with 3 integrated drivers synchronous Buck controller for
the CORE VR, and a single phase Buck controller for the
AXGVR. The RT8876AadoptsG-NAVPTM (GreenNative
Adaptive Voltage Positioning), which is Richtek's
proprietary topology derived from a finite DC gain
compensator with current mode control, making it an easy
setting PWM controller, meeting all Intel CPU
requirements of AVP. Based on the G-NAVPTM topology,
the RT8876Aalso features a quick response mechanism
for optimizingAVP performance during load transient. The
RT8876A supports mode transition function with various
operating states. A serial VID (SVID) interface is built in
the RT8876A to communicate with Intel VR12/IMVP7
compliant CPU. The RT8876A supports VID on-the-fly
function with three different slew rates : Fast, Slow and
Decay. By utilizing theG-NAVPTM topology, the operating
frequency of the RT8876Avaries 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
RT8876A integrates a high accuracy ADC for platform
setting functions, such as no-load offset or over current
level.
z 3 Embedded MOSFET Drivers at the CORE VR
z G-NAVPTM Topology
z Serial VID Interface
z 0.5% DAC Accuracy
z Differential Remote Voltage Sensing
z Built-in ADC for Platform Programming
z Accurate Current Balance
z System Thermal Compensated AVP
z Diode Emulation Mode at Light Load Condition for
Single Phase
z Fast Transient Response
z 1.1VINITIAL / 0.0VINITIAL for both Rails at Startup
z Power Ready Indicator
z Thermal Throttling
z Current Monitor Output
z OVP, UVP, OCP, OTP, UVLO
z External No-load Offset Setting for both Rails
z DVID Enhancement
z 56-Lead WQFN Package
z RoHS Compliant and Halogen Free
Applications
z VR12/IMVP7 Intel Core Supply
z Notebook/Desktop Computer/ Servers Multi-phase CPU
Core Supply
z AVP Step-Down Converter
Simplified Application Circuit
RT8876A
VR_RDY PHASE1
MOSFET
PHASE2
PHASE3
MOSFET
MOSFET
VRHOT
VCLK
V
V
CORE
To CPU
VDIO
PWMA
RT9612
MOSFET
AXG
ALERT
Copyright 2012 Richtek Technology Corporation. All rights reserved.
©
is a registered trademark of Richtek Technology Corporation.
DS8876A-02 October 2012
www.richtek.com
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