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.
Features
5V Power Supply
2/3-Phase Power Conversion with Automatic Phase
Selection
8-bit VID Interface, Supporting Intel VRD11/VRD10.x
and AMD K8, K8_M2 CPUs
VR_HOT and VR_FAN Indication
Precision Core Voltage Regulation
Power Stage Thermal Balance by DCR Current
Sensing
Adjustable Soft-start
Over-Voltage Protection
Adjustable Frequency and Typical at 300kHz per
Phase
Power Good Indication
32-Lead VQFN Package
RoHS Compliant and 100% Lead (Pb)-Free
Applications
Intel
®
/AMD New generation microprocessor for Desktop
PC and Motherboard
Low Output Voltage, High power density DC-DC
Converters
Voltage Regulator Modules
Ordering Information
RT8803A
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)
Pin Configurations
(TOP VIEW)
VID_SEL
VID0
VID1
VID2
VID3
VID4
27
VID5
26
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.
32
31
30
29
28
25
24
23
22
VTT/EN
VR_Ready
FBRTN
FB
COMP
SS
VR_FAN
VR_HOT
VID6
21
20
19
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
33
GND
VID7
VDD
PWM3
PWM2
PWM1
ISP1
ISP2
ISP3
18
17
TSEN
IMAX
DVD
RT
OFS
ADJ
VQFN-32L 5x5
All brandname or trademark belong to their owner respectively
DS8803A-05 August 2007
www.richtek.com
1
ISN23
ISN1
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
