relay good enough for fast (100Mhz) Ethernet

[Amnon Pomerants]

Hi all,
In my design i have to accommodate two possible paths for a incoming Fast
Ethernet link.
The selection of the exact path must be made already on the analog section.
I thought about using a double relay to direct the TPIP/N and the RTIP/N
signals into the proper PHY.
Can anyone recommend please such a relay with low capacitance that will do
the trick for 100Mhz as well (the selection is not done in real time, only
during card initialization)
Any help will be appreciated.
Thanks

 

[Don Pearce]

Hi all,
In my design i have to accommodate two possible paths for a incoming Fast
Ethernet link.
The selection of the exact path must be made already on the analog section.
I thought about using a double relay to direct the TPIP/N and the RTIP/N
signals into the proper PHY.
Can anyone recommend please such a relay with low capacitance that will do
the trick for 100Mhz as well (the selection is not done in real time, only
during card initialization)
Any help will be appreciated.
Thanks

Any of these - I've used them happily at over 1GHz.

http://www.teledynerelays.com/electroprod.asp

d

_____________________________

http://www.pearce.uk.com

 

[Rene Tschaggelar]

Hi all,
In my design i have to accommodate two possible paths for a incoming Fast
Ethernet link.
The selection of the exact path must be made already on the analog section.
I thought about using a double relay to direct the TPIP/N and the RTIP/N
signals into the proper PHY.
Can anyone recommend please such a relay with low capacitance that will do
the trick for 100Mhz as well (the selection is not done in real time, only
during card initialization)
Any help will be appreciated.

We used SPDT DIL Reed relais with screens between switch and coil
for 100MHz. Use SPDT and terminate the not used path into 50 Ohms.
This way you can achieve somewhat above 30dB isolation.
They cost in the order of 10$ each.

Rene

 

[John Larkin]

Hi all,
In my design i have to accommodate two possible paths for a incoming Fast
Ethernet link.
The selection of the exact path must be made already on the analog section.
I thought about using a double relay to direct the TPIP/N and the RTIP/N
signals into the proper PHY.
Can anyone recommend please such a relay with low capacitance that will do
the trick for 100Mhz as well (the selection is not done in real time, only
during card initialization)
Any help will be appreciated.
Thanks

Aromat TQ series.

John

 

[Jamie]

if you must use hardware then i guess low profile reed relays may
work.
using solidstate devices may get a little trick and expensive
for switching 100 Mhz with the load factor that may take place on
the Cat wire.

 

[Mac]

Hi all,
In my design i have to accommodate two possible paths for a incoming
Fast Ethernet link.
The selection of the exact path must be made already on the analog
section. I thought about using a double relay to direct the TPIP/N and
the RTIP/N signals into the proper PHY. Can anyone recommend please such
a relay with low capacitance that will do the trick for 100Mhz as well
(the selection is not done in real time, only during card
initialization)
Any help will be appreciated.
Thanks

I know you asked for relays, but there are MOSFET switches specifically
designed for switching ethernet. For example, IDT (www.idt.com) has a line
of products called "quickswitch." One example is the IDTQS3VH125. The
datasheet specifically mentions 10/100 ethernet.

I used a quickswitch (don't remember the exact part number) on a single
board computer to route the ethernet between two different points. The way
it worked was that there was an ethernet port on the front of the board,
and another one on the back. The BIOS had an option allowing the user to
select either the front or back port. Depending on the BIOS setting, a
general purpose IO pin from the processor was set high or low. This pin
was routed to the quickswitch, which acted as a mux.

Good luck.

--Mac