[SI-LIST] Series termination

Hi

I am designing a transceiver that will use series termination. The IO is 
a differential driver, so while one pin will be connected to high 
voltage (external pin) through a series resistor of 50ohms, the other 
will be connected to gnd (and the connectivity switches to toggle the 
output) the same way.

when I started design I thought it should be good enough to terminate in 
this way, because I had seen many single-ended (as opposed to 
differential) drivers doing the same. However now I'm worried whether 
the differential termination will be good enough for a 100ohm termination.

Specifically I'm concerned about the return path for the current. As I 
see it, it is something like: into the negative pin, through 50ohm, gnd, 
gnd-vdd coupling, vdd, 50ohms resistor, positive going pin. I doubt 
whether gnd-vdd coupling will be good enough for high speed data 
transfer (300-6000Mbps). On the other hand I believe similar issues 
should come for single-ended drivers.

Can someone point to any reading material. Also any criticisms of the 
approach are welcome.

Regards
Vinayak

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