Doug Brooks wrote:
> 
> Various sources (e.g. IPC) have formulas for propagation
> delay for microstrip and stripline configurations. Does
> anyone know of a formula for propagation time in a
> DUAL stripline configuration? Or is the stripline
> configuration close enough?

Hi Doug, 

I have calculated prop delay in a round about manner. 
I'll reference you to a Motorola ECL Design Apps book 
they published a while ago. 

In it prop delay is given as   pd = (L*C)^0.5

L = inductance of the trace/inch  (or whatever) 
C = capacitance of the trace/inch (    "      )

I use *any* calculation I can get my hands on to 
get the C.  L is a function of the trace itself. 
Typically about 20 nH/inch. 

I then drop these values into   pd = (L*C)^0.5 
for a prop/inch number, then simply multiply 
by the length of the trace for total delay. 

If this all sounds like flying by the seat of 
my pants, I agree.  But, I would challange 
anyone to give me a reasonably accurate 
measure of trace inductance to 3 decimal places. 

I could be well wrong, so I would appreciate any ideas. 

Regards,  

Doug 

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   The comments and opinions stated herein are mine alone,
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