The 100 ohm differential termination on the input (pins 6 and 7) will
only properly terminate a fully differential signal (not a single-ended
signal), but only if the device driving this input can effectively
drive this differential load, and the input traces are either 50-ohm
lines or a 100-ohm differential pair. So, without knowing what is
driving this fanout buffer, we can't answer this first part properly.
The pull-down resistors on the two sets of differential outputs will
adequately bias the emitter follower outputs. However, they will not
help to terminate a long PCB trace or transmission line. If the output
traces are short (an inch or less), then you'll probably be OK.
However, if the lines are longer than this, then you'll have to
consider a different termination scheme to precent reflection problems.
Very good results can be obtained by putting proper terminations at
the far end of the lines (opposite end from the driver). Proper ECL
terminations will present a 50ohm load that is terminated to a VCC-2V
potential. This properly terminates the 50-ohm transmission line (to
avoid reflections), and also presents a proper bias to the emitter
follower outputs of the driver. A split termination can be used on
each line which presents the thevenin equivalent of 50ohm to VCC-2V.
For typical 5V ECL/PECL applications, a split termination is made by
putting an 82ohm resistor from VCC to the line, and then a 130ohm
resistor from the line to VEE. If you are routing the signals
differentially, then other delta or Y style terminations can be used
which don't draw standing power like the spit termination does.
Lots of good information on proper handling of ECL/PECL circuits can be
found on Freescale Semicondutor's website (formally On Semiconductor,
formally Motorola Semiconductor).