[SI-LIST] Drivers on a 50Ohm line

Hi All,

I have a simple question, for which I'm yet to find a complete answer.

A standard PCB trace has an impedance of 50Ohms.  Does this imply that,
say, for a 2.5V signal, a driver must be able to drive 2.5/50 =3D 50mA =
of
current on this signal to allow for a full swing of the signal?

If this is the case, then how can a driver, such as a clock oscillator,
which has a drive strength in the order of 20-30mA drive a buffer
through a 50ohm line without the voltage being attenuated?  This would
get accentuated at 3.3V, or 5V where the current requirement would
increase.

Any thoughts appreciated

Thanks

-Nitin
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List FAQ wiki page is located at:
                http://si-list.org/wiki/wiki.pl?Si-List_FAQ

List technical documents are available at:
                http://www.si-list.org

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: