distributed amplifier site:edaboard.com

Hi!

I am looking in hmc459 datasheet (http://www.hittite.com/content/docum...eet/hmc459.pdf) and I wonder how it is possible to get 26 dBm saturated output power in 50 Ohm load at low frequency (even from DC) with supply voltage of 8 V?
The output voltage swing should be 12,6 Vp-p! But Vs=8 V....

I feel the Vrms is around 4.5V and hence the 26dBm