Vitesse VSC8221 Ethernet PHY for Media Converter Application

[Saturn929]

Hi everyone,

I'm currently designing a media converter board using Vitesse VSC8221. Just as an FYI, the documents for this product are all available at **broken link removed**.

When I say media converter, I actually meant SFP interface for fiber medium to RJ45-CAT5 for copper medium, and vice versa.

Now, I've studied the datasheet and application notes of the chip quite extensively, and the chip does offer a 'Media Converter' mode (Datasheet:Section 4.2age 2). The application diagram for this mode is as shown below.



While I can use this mode, one drawback of this mode is that it only supports 1000BASE-T to 1000BASE-X. It doesn't support conversion to/from 10/100BASE-TX.


But in the datasheet, it's also showing a mode where it supports all 10/100/1000BASE-T to GBIC/SFP interface. The application diagram is as shown below.



Now, my questions are:

1. Can I use the second mode to do my media conversion? I know there are copper SFP also, but since the interface is specified as SFP, what's stopping me from using an optical transceiver SFP?
2. If no, does this chip allow me to do a one-chip media conversion that supports all 10/100/1000BASE-T, even if that means I can't use the 'Media Converter' mode? I've read the datasheet and I'm still not sure of the answer.

I hope someone can offer some advice on the matter. Thank you so much in advance.