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RT8877C
Dual-Output PWM Controller for AMD SVI2 CPU Power Supply
General Description
The RT8877C is a 4 + 2 phases PWM controller. Moreover, it is compliant with AMD SVI2 Voltage Regulator Specification to support both CPU core (VDD) and Northbridge portion of the CPU (VDDNB). The RT8877C features CCRCOT (Constant Current Ripple Constant OnTime) with G-NAVP (Green-Native AVP), which is a Richtek's proprietary topology. G-NAVP makes it an easy setting controller to meet all AMD AVP (Active Voltage Positioning) VDD/VDDNB requirements. The droop 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 controller also uses the interface to issue VOTF Complete and to send digitally encoded voltage and current values for the VDD and VDDNB domains. It can operate in single phase and diode emulation mode and reach up to 90% efficiency in different modes according to different loading conditions. The RT8877C provides special purpose offset capabilities by pin setting. The RT8877C also provides power good indication, over current indication (OCP_L) and dual OCP mechanism for AMD SVI2 CPU core and NB. It also features complete fault protection functions including over voltage, under voltage and negative voltage.
Features
z
z z z z
z z z z z z z z z
4/3/2/1-Phase (VDD) + 2/1/0-Phase (VDDNB) PWM Controller G-NAVPTM Topology Support Dynamic Load Line and Zero Load Line Diode Emulation Mode at Light Load Condition SVI2 Interface to Comply AMD Power Management Protocol Build-in ADC for VOUT and IOUT Reporting Immediate OV, UV and NV Protections and UVLO Programmable Dual OCP Mechanism 0.5% DAC Accuracy Fast Transient Response Power Good Indicator Over Current Indicator 52-Lead WQFN Package RoHS Compliant and Halogen Free
Applications
z z
AMD SVI2 CPU Desktop Computer
Simplified Application Circuit
RT8877C OCP_L PWM1 PWM2 SVC To CPU SVD SVT PWM3 PWM4 PWMA1 PWMA2
RT9624A RT9624A RT9624A RT9624A RT9624A RT9624A
MOSFET MOSFET MOSFET MOSFET MOSFET MOSFET
VVDD
VVDDNB
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS8877C-00
November 2012
www.richtek.com 1
RT8877C
Ordering Information
RT8877C Package Type QW : WQFN-52L 6x6 (W-Type) Lead Plating System Z : ECO (Ecological Element with Halogen Free and Pb free)
Note : Richtek products are :
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Pin Configurations
(TOP VIEW)
PWM3 PWM2 PWM1 NC NC NC DVD NC NC NC PWMA1 PWMA2 TONSETA
52 51 50 49 48 47 46 45 44 43 42 41 40
RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes.
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Marking Information
RT8877CZQW : Product Number
Copyright © 2012 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com 2
RGND IMON V064 IMONA VDDIO PWROK SVC SVD SVT OFS OFSA SE.