RT8876A_14 Datasheet, PDF (1/50 Pages) Richtek Technology Corporation – Dual Channel PWM Controller

®
RT8876A
Dual Channel PWM Controller with 3/2/1 Phase for CORE VR
and Single Phase for AXG VR
General Description
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
AXG VR. The RT8876A adopts G-NAVP^TM (Green Native
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-NAVP^TM topology,
the RT8876A also features a quick response mechanism
for optimizing AVP 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 the G-NAVP^TM topology, the operating
frequency of the RT8876A 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
RT8876A integrates a high accuracy ADC for platform
setting functions, such as no-load offset or over current
level.
Features
z VR12/IMVP7 Compatible Power Management
z 3/2/1 Phase for CORE VR and Single Phase for AXG
VR
z 3 Embedded MOSFET Drivers at the CORE VR
z G-NAVP^TM 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 1.1V_INITIAL / 0.0V_INITIAL 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
To CPU
RT8876A
VR_RDY PHASE1
VRHOT
VCLK
PHASE2
PHASE3
VDIO
ALERT
PWMA
MOSFET
MOSFET
MOSFET
RT9612
MOSFET
V_CORE
V_AXG
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
DS8876A-03 January 2014
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
1