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Xconnect Post subject: Buffer -- to 50Ohm PCB constraint Posted:
Tue Jan 13, 2009 12:29 am Lieutenant Joined: Thu Jan
08, 2009 10:27 pm Posts: 2 I have a buffer output (1MHz output
at max) that needs to connect to a 50Ohm line (that runs the length
of the PCB board)to be measured for frequency. There is about 6inches
between the connector edge of this buffer output to the point where
it meets up(becomes 50 ohms) on the PCB stripline. At these
low frequencies is it still worthwhile to establish the 50 ohm impedance
closer to the connector or perhaps just using a low value series R close
to the connector will suffice to mitigate reflections to the frequency
counter? Top nubbage Post subject: Posted: Thu
Jan 15, 2009 6:56 am General Joined: Fri Feb 17,
2006 12:07 pm Posts: 218 Location: London UK IMHO at such
a low frequency anything goes, but to give peace of mind, you could
insert a small T pad giving 6dB attenuation in a 50 ohm circuit, near
the buffer output. I have often made these up from carbon film surface
mount chip resistors; they give enough isolation against mismatches
to avoid problems _________________ At bottom, life is all
about Sucking in and blowing out.
Posted 11/12/2012
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