Table 57. Recommended Gmch Dac Components - Intel 855GM Design Manual

Integrated Graphics Display Port
The analog switch should exhibit a low "on" resistance (< 8 Ω) and low parasitic capacitance (<10 pF).
The output routing from the analog switch should be routed as single-ended, 37.5-Ω impedance to the
75-Ω termination resistors that are located near the VGA connector on the motherboard and the VGA
connector on the docking station. The single-ended routing after these 75-Ω termination resistors to the
pi-filter and then to the VGA connector should be ideally 75-Ω. The recommended routing of the
termination resistors is shown in Figure 79.

Table 57. Recommended GMCH DAC Components

Component
R1
1
Refset
C1
C2
C
D
FB
Analog
Switch
NOTE: Not needed when using 855GME platform with external graphics only.
162
Recommended DAC Board Components
Value Tolerance
75.0 Ω
1%
127.0 Ω
1%
0.1 uF 20%
0.01 uF 20%
3.3 pF 10%
PAC DN006 -------
75 Ω @ 100 MHz
--------
------- -------
Power
1/16 W
1/16 W
-----
-----
-----
350 mW ESD diodes for VGA, SOIC package
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Rated for a continuous
channel current of
Texas Instruments SN74CB3Q3306
100mA (min)
®
Intel 855GM/855GME Chipset Platform Design Guide
Type
SMT, Metal Film
SMT, Metal Film
SMT, Ceramic
SMT, Ceramic
SMT, Ceramic
California Micro Devices –
Or equivalent diode array
MuRata* BLM11B750S
Ron < 8 Ω , Con < 10 pF
R