Communication Concepts 2M 1KW Amateur Application Note - Manual (Page 14)

14
RF Reference Design Data
Freescale Semiconductor
MRFE6VP61K25H MRFE6VP61K25HS 2 Meter Amateur
APPENDIX B
Mounting Tips
An Arlon TC350 PCB was chosen for its high thermal
conductivity.
Mounting is done on a copper heat spreader. Flatness
under the transistor flange is critical; good flatness is
mandatory for both RF and thermal performance. The
transistor is mounted on the heat spreader using a thin layer
of thermal compound.
When using bolt--down mounting do not over--torque the
part. Over tightening the fasteners can deform the transistor
flange and degrade both the RF and thermal performance,
as well as long term reliability.
To reach optimum performance, the PCB must be
soldered to the copper heat spreader. This is usually done
using a hotplate and solder paste. It is critical that the
soldering near the transistor and connectors is free of voids
and is of high quality in to order to achieve best performance
and reliability.
Refer to AN1617 Mounting Recommendations for Copper
Tungsten Flanged Transistors. Go to http://freescale.com/rf
and select Documentation/ Application Notes -- AN1617 for
more information.