RT8803A_11 Datasheet, PDF (1/27 Pages) Richtek Technology Corporation – 2/3-Phase PWM Controller for High-Density Power Supply

RT8803A
2/3-Phase PWM Controller for High-Density Power Supply
General Description
The RT8803A is a 2/3-phase synchronous buck controller
specifically designed to power Intel^®/ AMD next generation
microprocessors. It implements an internal 8-bit DAC that is
identified by VID code of microprocessor directly. RT8803A
generates VID table that conform to Intel^® VRD10.x and
VRD11 core power with 6.25mV increments and 0.5%
accuracy.
RT8803A adopts innovative time-sharing DCR current sensing
technique to sense phase currents for phase current balance,
load line setting and over current protection. Using a common
GM to sense all phase currents eliminates offset and linearity
variation between GMs in conventional current sensing
methods. As sub-milli-ohm-grade inductors are widely used
in modern motherboards, slight offset and linearity mismatch
will cause considerable current shift between phases. This
technique ensures good current balance at mass production.
Other features include over current protection, programmable
soft start, over voltage protection, and output offset setting.
RT8803A comes to a small footprint package with
VQFN-32L 5x5.
Ordering Information
RT8803A
Package Type
QV : VQFN-32L 5x5 (V-Type)
Note :
Lead Plating System
P : Pb Free
G : Green (Halogen Free and Pb Free)
Richtek 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.
Features
z 5V Power Supply
z 2/3-Phase Power Conversion with Automatic Phase
Selection
z 8-bit VID Interface, Supporting Intel VRD11/VRD10.x
and AMD K8, K8_M2 CPUs
z VR_HOT and VR_FAN Indication
z Precision Core Voltage Regulation
z Power Stage Thermal Balance by DCR Current
Sensing
z Adjustable Soft-start
z Over-Voltage Protection
z Adjustable Frequency and Typical at 300kHz per
Phase
z Power Good Indication
z 32-Lead VQFN Package
z RoHS Compliant and 100% Lead (Pb)-Free
Applications
z Intel^®/AMDNew generation microprocessor for Desktop
PC and Motherboard
z Low Output Voltage, High power density DC-DC
Converters
z Voltage Regulator Modules
Pin Configurations
(TOP VIEW)
32 31 30 29 28 27 26 25
VTT/EN 1
VR_Ready 2
24 _VID7
23 _VDD
FBRTN ³
FB 4
COMP 5
SS 6
VR_FAN 7
VR_HOT 8
22 PWM3
GND
21 PWM2
20 _PWM1
19 ISP1
33
18 _ISP2
17 ISP3
9 10 11 12 13 14 15 16
VQFN-32L 5x5
DS8803A-06 April 2011
www.richtek.com
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