CM3109
Application Information (cont’d)
VCC
VDDQ
CVDDQ
47uF
VDDQ
VCC
VDDQSEL
VTT
CVCC
47uF
VDDQSEL
BOOTSEL
VSENSE
GND
FSBSEL
SD
GMCHVCCP
RVDDQSEL
4.7K
CVTT
FSBSEL
0.1uF
220uF
GMCH_EN
Figure 18. Typical Front Side Bus with Suspend to RAM Application Circuit
shutdown periods. The V SEL input ensures that
DDQ
The above diagram shows the CM3109 connected to
the CM3109 is in Front Side Bus mode, and the BOOT-
SEL from the GMCH ensures the right Microprocessor
the Intel 865 GMCH Front Side Bus V pin GMCH-
TT
VCCP. The Enable signal GMCH_EN is used to shut
down the output of the CM3109 to save power during
V
voltage is applied.
TT
V
DDQSEL
FSBSEL
VTT
NOTE
VCC (CPU Core)
GMCH_EN
"1"
Don’t Care
VDDQSEL/2
(see note 1)
For DDR
Open or "0"
Open or "0"
"0"
"1"
1.225V
1.45V
For FSB
For FSB
Note 1:Assumes VDDQ and VDDQSEL are tied
together in DDR application.
GMCHVCCP
Figure 19. Front Side Bus Timing diagram
Table 1: V Output Selection Truth Table.
TT
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