Well, that is a hard question to answer,
not knowing more about the circuit.
The daisy chain may help reduce reflections
from stubs, so it might be good from a signal
integrity "transmission line theory" point of
view, but that might not be the crucial issue.

By daisy chaining, you GUARANTEE that the
clock pulses will arrive at the devices AT
DIFFERENT TIMES.
You might be better off using a "star" pattern,
where each device has its own clock line from
the origin, and they are all approximately the
same length. Then they all trigger at the same
time.

I would ask the engineer what the priorities are....


Jack






Pcb Man <[log in to unmask]>@IPC.ORG>
27Aug2002 07:09 AM

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Subject:  [DC] Clock Signal routing
Retain Until: 09/26/2002 Retention Category: G90 - Information and Reports
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Hi Everyone,

I would like to know whether DAISY chain type routing is ok for routing
CLOCK signals. Will this be of any help with respect to the signal
integrity point of view?

As far as I know about DAISY chaining, it unnecessarily increases the
length of any signal to which this technique is applied for routing.

Which is the best possible way of shielding the clock signals ( the closk
signal on my board comes out from a BGA)

Any suggestions/answers ?



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