I am looking for advice on clock distribution for an Oil and Gas well-monitoring application. The tool is likely to be 2m in length and I have to distribute a 25MHz clock to up to 10 daughter boards along that length. Some daughter boards contain up to 24 devices that need the clock. No hot-plugging will occur.
My current thinking is to transmit the clock using multidrop and have built a module containing a SN65MLVD200A as a driver module. I picked this M-LVDS part as I have a relatively slow clock; I have read TI documents that state LVDS is both good for multidrop (SLLD009 bottom of page 6-6) and not good (SNLA113B bottom of page 3).
I planned to put receivers on the main board to make the stub lengths as short as possible but then I need to get the signal onto the daughter cards and distributed thereon.
My questions begin therefore:
1) Is M-LVDS the best option for the main clock distribution?
2) How best to transfer that clock onto a daughter board that might have many clock loads? I cannot find M-LVDS repeaters, only a 1:4 fanout device. Can I use an LVDS repeater?
3) There is a much wider choice of LVDS single/dual receivers in small (SOT) packages than M-LVDS (packages without legs are not really option). Is it common to use LVDS receivers with M-LVDS drivers?
I have read many TI application notes now and I'm going round and round. I need someone with more experience to make some suggestions, on parts, topology, anything; all comments are welcome.