鈥?/div>
52鈥揕ead LQFP Packaging
The processor clock outputs of the MPC980 can be programmed to
provide 50, 60 or 66MHz. Under all processor output frequencies the PCI
clock outputs will be equal to one half the processor clock outputs. The
PCI outputs will run synchronously to the processor clock outputs. There
are a total of ten output clocks which can be split into a group of four and a
group of six. Either group can be configured as processor or PCI clocks.
Each of the outputs can drive two series terminated transmission lines
allowing for the driving of up to twelve independent processor loads and
eight PCI clock loads. A pin selectable option is available to delay the PCI
clock outputs relative to the processor clocks. The amount of delay is a
function of the processor clock frequency and varies from 2ns to 6ns.
FA SUFFIX
52鈥揕EAD LQFP PACKAGE
CASE 848D鈥?3
The output jitter of the the PLL at 66MHz output is
鹵150ps
peak鈥搕o鈥損eak, cycle鈥搕o鈥揷ycle (the worst case deviation of the clock
period is guaranteed to be less than
鹵150ps).
The skews between one processor clock and any other processor clock (or one
PCI clock to any other PCI clock) is 350ps. The worst case skew between the processor clocks and the PCI clocks is 500ps.
An output enable pin is provided to tristate all of the outputs for board level test. In addition a testing mode is provided to allow
for the bypass of the PLL鈥檚 for board level functional debug.
Pentium is a trademark of Intel Corporation. PowerPC is a trademark of International Business
Machines Corporation.
1/98
漏
Motorola, Inc. 1998
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