level shifting high speed signals
I have a host of differential signals from a board thats 3.3V. Now, I need to interface it to a board that can accept 2.5V. Now, is it possible to use a standard level shifter like this ?


As comments point out, the part you found is only capable of level-shifting single-ended signals at up to 200 Mbps. You said your maximum rate is 1 GHz.

You can level shift a clock signal by simply ac-coupling and re-biasing:







simulate this circuit &ndash; Schematic created using CircuitLab

With the given resistor values, the bias at the Rx inputs is at Vcc/2. If you need a different common mode voltage, you need to find other resistor values that give that value as voltage divider, and also form a 50-ohm termination (assuming matching a 50-ohm transmission line)

For data signals, you can use the same scheme if the data is balanced (contains equal numbers of 0's and 1's over a span of a few dozen bits). If the data is not balanced, you may have to find an appropriate level shifter for your data rate and source/receiver voltage levels. 


  Now, my clock is going from one board to another board. And I foresee a degradation of the performance. How can I rectify that ?


Be sure to use impedance-matched transmission lines to connect between the boards. Be sure to use an appropriate technology for the distance you need to cover.