Ramdac Component And Routing Guidelines - Intel 810A3 Design Manual

Layout and Routing Guidelines
Figure 4-35. RAMDAC Component and Routing Guidelines
Place LC filter components &
high frequency de-coupling
capacitors as close to the power
pins as possible.
Graphics
Chip
Pixel
Clock
(From
DPLL)
Place the
Reference
Resistor in Close
Proximity to the
IREF Pin
NOTE: Diodes D
4-34
Analog
Power Plane
Lf
1.8V
1.8V Board
LC
Cf
Power Plane
Filter
V C C D A C A 1 /
R E D
V C C D A
V C C D A C A 2
RAMDAC
G R E E N
Blue
I W A S T E IREF V S S D A C A
Rset
via Straight Down to the Ground Plane
, D are clamping diodes and may not be necessary to populate.
1 2
1.8V Board
Power Plane
1.8V Board
Power Plane
D1
37.5 Ω Route
Red Route
D2
1.8V Board
Power Plane
D1
37.5 Ω Route
Green Route
D2
1.8V Board
Power Plane
D1
37.5 Ω Route
Blue Route
D2
Place Diodes Close
to RGB Pins
Avoid Routing
Toggling Signals in
this Shaded Area.
- Match the RGB Routes
- Make Spacing Between the RGB Toutes a Min. of 20 mils
Intel
Place the pi-Filter in close proximity
to the VGA connector.
75 Ω Routes
F B
C1
C2
Rt
pi Filter
75 Ω Routes
F B
V G A
C1
C2
Rt
pi Filter
75 Ω Routes
F B
C1
C2
Rt
pi Filter
®
810A3 Chipset Design Guide