Output Buffer - Megafunction ALTIOBUF

Hello,

I'm using a Cyclone III device.

I want to output an LVDS clock around 100MHz. The frequency of the differential clock is not as much of a problem as the propagation delay induced by the output buffer.

I understand I have to instanciate a "global" output buffer between my clock signal and the output pad. I have two questions :

- How do specify the LVDS electrical format?

- What's a typical value for propagation delay for this ALTIOBUF function?

Thanks all!

A.