[SI-LIST] Re: SMA for launching 5-10Gbs signals
- From: ray_waugh@xxxxxxxxxxx
- To: si-list@xxxxxxxxxxxxx
- Date: Wed, 17 Jul 2002 10:58:33 -0600
This is an age-old issue with we RF and microwave designers.
First, you need to avoid a shunt capacitance at the launch from SMA to
microstrip (or, in my case, coplanar waveguide with ground plane). This means
having a 50 ohm microstrip line with a linewidth of 0.040" or more (wider than
the connector pin). If that line is too wide for your system, you can
transition to the final linewidth a short distance from the SMA connector.
Second, you need to cut back that pin to something like two diameters (about
0.050"). This also eliminates shunt capacitance at the connector/board
interface.
Third, you need to cover the exposed crescent of Teflon on the ground plane
side by using a generous fillet of solder. I can send a PDF file with a photo
to anyone who is interested.
Ray Waugh
Agilent Technologies
-----Original Message-----
From: D_Enos@xxxxxxxxxxxxxxxxxxxxxx
[mailto:D_Enos@xxxxxxxxxxxxxxxxxxxxxx]
Sent: Wednesday, July 17, 2002 9:42 AM
To: ray_waugh@xxxxxxxxxxx
Cc: si-list@xxxxxxxxxxxxx
Subject: Re: [SI-LIST] Re: SMA for launching 5-10Gbs signals
I would be interested in what you mean by properly mounted. We have
experienced some of the same problems with the edge launch SMAs.
ray_waugh@xxxxxxxxxxx@freelists.org on 07/17/2002 11:15:45 AM
Please respond to ray_waugh@xxxxxxxxxxx
Sent by: si-list-bounce@xxxxxxxxxxxxx
To: si-list@xxxxxxxxxxxxx
cc:
Subject: [SI-LIST] Re: SMA for launching 5-10Gbs signals
My colleagues and I have had great success with the end launch SMA
connectors, such as the 142-0701-881. Properly mounted, they work very
nicely to 18 GHz.
Ray Waugh
Agilent Technologies
-----Original Message-----
From: zanella, fabrizio [mailto:zanella_fabrizio@xxxxxxx]
Sent: Wednesday, July 17, 2002 8:49 AM
To: SI List (E-mail)
Subject: [SI-LIST] SMA for launching 5-10Gbs signals
We have test boards which are used for testing the quality of 2-4Gbs
signals across backplanes. The serial signals can be generated from
evaluation boards provided by the serdes vendors or signal generators.
We've been using the Johnson Components surface mount SMA, part number
142-0711 on these test boards. One problem is that at times the cable
pulls
these SMAs off the boards, including the pads. Another concern is whether
these SMAs can be used for launching signals at 5-10Gbs.
Does anyone have suggestions for other SMA types which make a stronger
connection to test boards and provide a good launch which can be used at
5-10Gbs?
thanks,
Fabrizio Zanella
Signal Integrity
EMC Corporation
fzanella@xxxxxxx
------------------------------------------------------------------
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:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List archives are viewable at:
//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
------------------------------------------------------------------
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:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List archives are viewable at:
//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
------------------------------------------------------------------
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:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List archives are viewable at:
//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:
