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Question asked by HansErik on Dec 5, 2017
Latest reply on Dec 12, 2017 by HansErik



The HMC8205 eval pcb board is a 0.010 ROGERS 4350B 2 layer.

For my application I need more layers, prefer 6 layers. I consider following stackup:

Layer 1-2: Rogers 4350B 0.010 (as eval board)

Layer 2-6 FR4


Layer 1: RF layer

Layer 2: gnd layer

Layer 3: power layer

Layer 4: signal  layer

Layer 5: signal layer

Layer 6: gnd (layer toward heat sink)  Soldermask relief


Total height  0.042" same as Flange height of the HMC8205 chip.


My concern is the jump in gnd, as HMC8205 has heatsink as gnd reference, and the RF trace has layer 2 as gnd layer. (RF trace routed in layer 1).  There will be added lot of gnd via to have a commen potential of gnd layers in the board. .


Do Aanalog Device have any experience/comments on my concern?