MagJack for wiznet w5200

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MORA99
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Location: Horsens, Denmark
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Posted by MORA99: Tue. Mar 27, 2012 - 08:16 AM
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I am looking to use W5200 in my next ethernet board, however from their datasheet, it seems my current magjack is not the best fit.
( http://www.sparkfun.com/products... )

The datasheet recommends a symmetric one to support auto-midx.
However I am not sure if the resistors are still needed, and how to make sure it has the correct inductance/capacitance.
Except for the resistors, the asymmetric one in the datasheet matches the one from sparkfun (ie. the one the datasheet does not recommend)

Does anyone know of a known working MagJack for W5200(W5100), preferably one that can be had from rs or element14/farnell.

Also: Both Atmega1284 and W5200 has exposed pad to GND, I am thinking about going to 4layers, is it ok to have vias directly in this exposed pad to connect to ground layer?
-And if so, how many vias is good practice ?

Tags:

Learning and Information, General Electronics, ATmega128, ATmega1284
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stevech
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Posted by stevech: Wed. Mar 28, 2012 - 05:21 AM
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why not buy WizNet's ready to use modules? Just plug it into your PC board. Comes with the RJ45. Like Wiz812MJ or 830MJ? Inexpensive.

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MORA99
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Posted by MORA99: Wed. Mar 28, 2012 - 05:57 AM
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Well, I am making more than 1 board, and dont really like the module solution.
Maybe the WIZ820io could work due to its small footprint, but really I am more for a complete onboard solution.

Also a module is 15USD+, whereas the chip+magjack+passives is ~8USD

However the modules shows a complete part number for the magjack used - RDA-125BAG1A :)

2.99USD@saelig
About the same at mouser, but MOQ 310pcs

(I already have a 812 in the drawer to prototype on)

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stevech
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Posted by stevech: Thu. Mar 29, 2012 - 03:33 AM
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MORA99 wrote:
Well, I am making more than 1 board, and dont really like the module solution.
Maybe the WIZ820io could work due to its small footprint, but really I am more for a complete onboard solution.

Also a module is 15USD+, whereas the chip+magjack+passives is ~8USD

However the modules shows a complete part number for the magjack used - RDA-125BAG1A :)

2.99USD@saelig
About the same at mouser, but MOQ 310pcs

(I already have a 812 in the drawer to prototype on)

Makes sense if you're going to build 1000.

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