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ethernet magnetics

Has anyone examined the actual wideband time-domain coupling behavior, like risetime and droop, of typical 10/100 Ethernet magnetics? I plan to try a couple that we have in stock, but I was wondering if anyone else has experience. We're considering using them in a non-Ethernet data coupling situation.

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John Larkin Highland Technology Inc

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jlarkin at highlandtechnology dot com

Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators

Reply to
John Larkin
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if they work, they have to be able to handle the LIT pulses.

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"They are unipolar positive-only electrical pulses of a nominal duration of 100 ns, with a maximum pulse width of 200 ns,"

You should be able to work backwards from that for the risetime.

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Les Cargill
Reply to
Les Cargill

Apparently, the Gigabit Ethernet specs require 350uH or more winding inductance. That should give you the droop. In a Coilcraft datasheet of the HPX2126L I found a graph that shows the upper frequency cut-off to be a little over 100MHz in a 100 Ohm setup, so the leakage inductance should be in the 150nH ballpark. That should give the risetime.

There are some more plots, and maybe one of those gives some clue about inter-winding capacitance, but it's nearly midnight here and tomorrow is going to be a long day...

Jeroen Belleman

Reply to
Jeroen

I've measured some "10/100"s before, finding inductance about that. I forget what I found for leakage.

Tim

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Reply to
Tim Williams

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