Recently I bought an ethernet switch controller based on the Realtek RTL8305NB chip. It was bought as a proof of concept for my robot. Unfortunately, the board is too big and I want to design my own 2-layer PCB (also to learn new stuff). I would like to use the same chip, but finding its datasheet is almost impossible (I even contacted manufacturer and few shops - no result). Does anybody know a similar chip? Why is the datasheet for RTL8305NB so hard to find?

What I need:

  • 10/100 MBPS,
  • at least 3 ports,
  • package for 2-layer board (not BGA).

I am new to the ethernet technology and I will appreciate any help and piece of advice.

  • \$\begingroup\$ It is not unusual for Ethernet product datasheets and reference manuals to be hidden behind NDAs, or sometimes be not available at all as the device manufacturer may have made the IC specifically for one customer. Are you open to a different device with similar functionality? \$\endgroup\$ – Peter Smith Nov 30 '15 at 10:56
  • \$\begingroup\$ Yes, I am open to a different chip with similar functionality. I was looking myself for other chips, but I am not familiar with all the ethernet terminology and abbreviations and I am afraid of designing PCB for a chip which won't work as the one I found (RTL8305NB). \$\endgroup\$ – Torcek Nov 30 '15 at 11:01

I have successfully used the Micrel KSZ8999. It may be a bit overkill, but there are numerous options

Datasheet here

Other sources are Microchip and Vitesse to name but two, although when I last used Vitesse, they were very NDA conscious.

Your switch is layer 2 managed, which is available in the Micrel part. I have not looked farther than this, as it provides a solution.


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