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R
Table 48. Recommended GMCH RAMDAC Components
Component
R1
Rset
C1
C2
C
D
FB
Figure 65 shows the recommended Rset placement.
Figure 65. Rset Resistor Placement
IREF ball
Resistor
Solder
Pads
8.1.5.
DAC Power Requirements
The DAC requires a 1.5-V supply through its two VCCADAC balls. The two may share a set of
capacitors, 0.1 µF and 0.01 µF, but this connection should have low inductance. Separate analog power
or ground planes are not required for the DAC.
However, since the DAC is an analog circuit, it is particularly sensitive to AC noise seen on its power
rail. Designs should provide as clean and quiet a supply as possible to the VCCA_DAC. Additional
®
Intel
852GM Chipset Platform Design Guide
Recommended DAC Board Components
Value
Tolerance
75.0 Ω
1%
128.0 Ω
1%
0.1 µF
20%
0.01 µF
20%
3.3 pF
10%
PAC DN006
-------
75 Ω @ 100 MHz
--------
GMCH Chipset
Rset
Resistor
Integrated Graphics Display Port
Power
1/16 W
1/16 W
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-----
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California Micro Devices – ESD diodes for VGA
350 mW
SOIC package or equivalent diode array
-------
128Ω, 1%, 1/16W
SMT metal film
resistor
Top Side of
Motherboard
Large via or multiple
vias straight down to
ground plane
Type
SMT, Metal Film
SMT, Metal Film
SMT, Ceramic
SMT, Ceramic
SMT, Ceramic
MuRata* BLM11B750S
Short, wide route
connecting the
resistor to the IREF
ball
No toggling signals
should be routed near this
reference resistor
133
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