I just got two ADF4350 eval boards (the single output ones) and have been running them up around 3GHz just fine but when I slowed the out freq down to 200MHz, the waveforms look AC coupled: there is a ~400ps wide rising pulse followed by a 400ps wide falling pulse at the proper freq. With 1nf caps it should not look like that. Any idea what is wrong? Both boards do it. Just going into a 50 ohm scope load.