General Description
The RT8877D is a 4 + 2 phases PWM controller, and is
compliant with AMD SVI2 Voltage Regulator Specification
to support both CPU core (VDD) and Northbridge portion
of the CPU (VDDNB). The RT8877D features CCRCOT
(Constant Current Ripple Constant On-Time) with the
G-NAVP (Green-Native AVP), which is Richtek's
proprietary topology. The 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 RT8877D provides special purpose offset capabilities
by pin setting. The RT8877D also provides power good
indication, over-current indication (OCP_L) and dual OCP
mechanism for AMD SVI2 CPU core and NB. It also
features fault protection functions, including over-voltage,
under voltage and negative voltage protections.

Features
 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
 AMD SVI2 CPU
 Desktop Computer