LVDS signal between two different power domains.

[engineman]

I am designing a LVDS RX/TX pair using TI's SN65LVDS179 parts. The parts are both 3.3V parts, but the two ends run off of slightly different power supplies. One side is running off of a -1.5V/1.5V supply and the other side is running off of a -2.5V/0.8V supply. The allowable common mode range of the parts (VSS+0.3V - VDD-1.2V) overlaps but I am having trouble keeping the signal within the allowable range of both parts (-1.8V - -0.4V). My signaling speeds are fairly slow ( ~36MHz ). What is the best way to keep the common mode in the right range? My first thought was a resistor ladder circuit like the one in the picture below. I have already tried adding the resistor ladder to the circuit and everything seems happy, but I keep wondering if this the best way to solve this problem, or is there a better way? Does anyone have any suggestions?

 

[dick_freebird]

If the transition density is high enough, you might
be able to capacitor-block it with just a centering
network at the destination end.

 

[engineman]

If the transition density is high enough, you might
be able to capacitor-block it with just a centering
network at the destination end.

So would that just involve adding two appropriately sized caps in series with the two inputs on one side of the resistor ladder circuit I posted earlier?