Q
Is the ballon a t Pin 8 & 9 required when using an oscillator to drive the
inputs or is the ballon just used to accommodate the mismatch of the external
clock input impedance on the Eval-board?
A
The Balun and the 50ohm resistor –these are for impedance matching on the input
of the AD9959.Source termination across the cable for the ext clock for eval
PCB. Also, the 50ohm source load termination does reduce the signal voltage
level by 6dB, but this is inherent in any properly terminated transmission
line. The alternative of leaving out the source termination resistor could lead
to distortion or higher jitter.
