I want to distribute 8 LVDS signals via a multiDROP bus hierarchy on a backplane board with the signal source in the center and 6 ports for slave boards to the right and another 6 ports to the left. The spacinig between the 12 slave board connectors is ~ 3 cm (1,2 inch).
I have read some application notes and found the bus LVDS and multiPOINT LVDS standards. My current approach would be to use a TTL to BLVDS or TTL to M-LVDS transmitter, place 100 ohm terminations at both ends and use standard LVDS buffer like the FIN1108 (https://www.onsemi.com/pub/Collateral/FIN1108-D.pdf) as repeaters (no termination). The repeater outputs will then interface via connectors to the LVDS inputs (FPGA) on the slave boards. Vias will be used to realize a short connection to the multidrop bus.
From my understanding the differences between LVDS and BLVDS/M-LVDS are only at the transmitter side. With the double termination the higher drive strength of BLVDS or M-LVDS will not result in too high input voltages at the standard LVDS receivers and the reduced slew rate shouldn't be a problem either.
- Can i use LVDS-standard receivers/repeaters in a multiDrop bus that is fed by a BLVDS or M-LVDS transmitter?
- If yes, any implications for routing like stub length?
- If no, what about using a dedicated bus transmitter and bus for the left and another one for the right arm?