The data sheet for the OPA689 specifies the output current into a 500 ohm load resistance.

The internal pulser set at 500 was used as input.
The clamp level was set at 0.
The pedestal was set at 2.345 V.

The 30 ohm series output resistor seems to give acceptable performance without too much degradation in signal rise or fall time,
and with reasonable freedom from ringing.