RT8801B Datasheet, PDF (1/23 Pages) Richtek Technology Corporation – Multi-Phase PWM Controller for K8 CPU Core Power Supply with Serial Programming Interface

Preliminary
RT8801B
Multi-Phase PWM Controller for K8 CPU Core Power
Supply with Serial Programming Interface
General Description
The RT8801B is a multi-phase synchronous buck controller
which is implemented with full control functions for AMD
K8 compliant CPU. The RT8801B could be operated with
2, 3 or 4 buck switching stages operating in interleaved
phase set automatically. The multiphase architecture
provides high output current while maintaining low power
dissipation on power devices and low stress on input and
output capacitors.
RT8801B is one of RichTek CPU core power solutions
which integrates a specific series programming interface
for the controller peration configuration. There are several
registers implemented for the specific parameters
configuration including VID for core power, and signal for
load current indication. User can program the configuration
of the parameters easily via the specific programming
interface. With the implementation of RT8801B, the part
provides more flexibility and feature for customers advanced
segment product design.
The RT8801B applies the DCR sensing technology newly
as well; with such a topology, the RT8801B extracts the
DCR of output inductor as sense component to deliver a
more precise load line regulation and better thermal
balance for next generation processor application. For
current sense setting, droop tuning, V_CORE initial offset
and over current protection are independent to
compensation circuit of voltage loop. The feature greatly
facilitates the flexibility of CPU power supply design and
tuning. The DAC output of RT8801B supports AMD CPU
with 6-bit VID input, precise initial value & smooth V_CORE
transient at VID jump. The IC monitors the V_CORE voltage
for over-voltage protection. Soft-start, over-current
protection and programmable under-voltage lockout are
also provided to assure the safety of microprocessor and
power system. The RT8801B comes to the package of
VQFN-32L 5x5.
Features
z Multi-Phase Power Conversion with Automatic
Phase Selection
z 6-bits AMD K8 DAC Output with Active Droop
Compensation for Fast Load Transient
z Smooth V_CORE Transition at VID Jump
z Power Stage Thermal Balance by DCR Current
Sense
z Hiccup Mode Over-Current Protection
z Adjustable Switching Frequency (50kHz to 400kHz
per Phase)
z Under-Voltage Lockout and Soft-Start
z High Ripple Frequency Times Channel Number
z 2-Wires Programming Interface
z Software Programmable VID
z 32-Lead VQFN Package
z RoHS Compliant and 100% Lead (Pb)-Free
Applications
z AMD K8 compliant Processors Voltage Regulator
z Low Output Voltage, High power density DC-DC
Converters
z Voltage Regulator Modules
Ordering Information
RT8801B
Package Type
QV : VQFN-32L 5x5 (V-Type)
Operating Temperature Range
P : Pb Free with Commercial Standard
G : Green (Halogen Free with Commer-
cial Standard)
Note :
Richtek Pb-free and Green products are :
`RoHS compliant and compatible with the current require-
ments of IPC/JEDEC J-STD-020.
`Suitable for use in SnPb or Pb-free soldering processes.
`100% matte tin (Sn) plating.
DS8801B-04 August 2007
All brandname or trademark belong to their owner respectively
www.richtek.com
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