Some (10x) of an Agilent low noise PHEMT ATF 54143, I am having some problems with a 300W 1296MHz Ham Tranceiver and keep blowing these little buggers up. Initially I thought it was coming in throughout the front end of the LNA, but now am pretty sure it is coming back up the receive line (from the transceiver receive port to the feed horn LNA). Despite the loss of magic smoke, when repaired,I am happy I am still getting a noise figure of ~0.3dB gain of 35dB at 1296MHz.