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ADVANCED INFORMATION
and limited characterization. They may change without notice. Contact Fairchild Semiconductor for current information.
describes products that are not in full production at the time of printing. Specifications are based on design goals
www.fairchildsemi.com
Features
¥ Four copies of CPU clock
¥ Eight copies of PCI Clock (Synchronous w/CPU clock)
¥ Two copies of IOAPIC clock @ 14.318MHz
¥ Two copies of 48MHz clock
¥ Three copies of REF clock @ 14.318MHz
¥ Reference crystal oscillator (14.318MHz)
¥ Spread Spectrum (-0.5%) clocking
¥ Power management controls
¥ Low frequency test mode
Applications
¥ 100MHz motherboard clock synthesizers for Pentium II
CPU based Desktop and Notebook Systems.
Description
The RC7100 is a clock synthesizer for 100MHz operation
on Pentium II based motherboard systems.
It contains 4 copies of the CPU clock, 8 copies of the PCI
clock, 3 copies of the REF clock, 2 copies of the 48MHz
clock and 2 copies of the IOAPIC clock. The CPU and PCI
clocks are generated through a phase locked loop and are
stable within 3mS after power-up meeting the Pentium II
stabilization specifications. The 48MHz clocks are
generated through a second phase locked loop.
The RC7100 accepts a 14.318MHz crystal as its
reference frequency and operates at a core voltage of 3.3V.
A 14.318MHz external clock can also be used instead of the
RC7100
100MHz Motherboard S ystem Cloc k
Block Diagram
REF0:2
XTAL_IN/
TCLK
XTAL_OUT
PWRDWN#
3
VDDref
VSSref
SPREAD#
SEL0
SEL1
SEL100/66#
PCISTOP#
CPUSTOP#
APIC0:1
2
VDDapic
VSSapic
CPUCLK0:3
PLL_1
PLL_2
4
VDDcpu
VSScpu
PCICLK0:6
7
VDDpci
VSSpci
PCICLKF
VDDcore
VSScore
48 MHz0:1
2
VDD48MHz
VSS48MHz
Rev. 0.5.3
Pentium is a registered trademark of Intel Corporation