Intel 855GME

January 2007 113
Intel
®
855GME Chipset and Intel
®
6300ESB ICH Embedded Platform Design Guide
4.8.3 Other GMCH Reference Voltage and Analog Power Delivery
4.8.3.1 GMCH GTLVREF
For GMCH, the GTLREF generation circuit has been broken down into three separate voltage
references: host data reference voltage (HDVREF[2:0]), host address reference voltage (HAVREF)
and host common clock reference voltage (HCCVREF). Maximum length from pin to voltage
divider for each reference voltage shall be less than 0.5 inches. Ten-mil wide traces are
recommended. GMCH VREF may be maintained as individual voltage dividers as shown in
Figure 55, Figure 56, and Figure 57.
Figure 55. GMCH HDVREF[2:0] Reference Voltage Generation Circuit
R1
49.9
1%
R2
100
1%
C1
1uF
+VCCP
K21
J21
J17
Intel
®
855GME
HDVREF0
HDVREF1
HDVREF2
0.1uF
GMCH_HDVREF
C2
Figure 56. GMCH HAVREF Reference Voltage Generation Circuit
R1
49.9
1%
R2
100
1%
C1
1uF
+VCCP
Y22
Intel
®
855GME
Chipset
HAVREF
C3
0.1uF
GMCH_HAVREF