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www.fairchildsemi.com
Features
Employs Fairchild’s proprietary Spread Spectrum
Technology
Reduces measured EMI by as much as 10dB
Supports up to 150MHz
Two skew-controlled copies of the CPU clock
¥
I
2
C programmable
Two copies of 3V66 clock
One copy 24MHz clock
One copy 48MHz clock
One copy IOAPIC
Two copy REF 14.318MHz clock (3.3V)
Eight copies PCI clock
Nine copies of SDRAM clock with one Free-running
Power down capability
Description
The RC7108 is a clock synthesizer for motherboard applica-
tions. It meets the requirements for 133MHz Whiting
chipset. The clock frequencies can be set with the 4 select
pins and/or be set via the I
2
C interface.
Block Diagram
IOAPIC/SEL_3V66
C
O
N
T
R
O
L
L
O
G
I
C
CPU0:1
3V660:1
FS0/PCI0
FS1/PCI1
PCI2:7
SDRAM0:7,_F
REF0/FREQ_APIC
PLL1
Spread
Spectrum
PLL2 USB
I2C
Registers
XTAL
OSC
REF1
X1
X2
SDATA
PWRDWN#
SCLK
48MHz/FS3
24MHz/FS2
RC7108
133MHz S pread S pec trum Cloc k for Motherboards