Hi Arthur
The majority of QFN packages are base on thermally/electrically enhanced lead-frame technology; the
bottom of the package provides the primary heat removal path, as well as excellent electrical grounding to
the PCB through an exposed pad (EP).
this and other recommendation for the QFN packages you can found it on the application note AN4530
http://www.freescale.com/files/sensors/doc/app_note/AN4530.pdf
have a good day
Hi Arthur
The majority of QFN packages are base on thermally/electrically enhanced lead-frame technology; the
bottom of the package provides the primary heat removal path, as well as excellent electrical grounding to
the PCB through an exposed pad (EP).
this and other recommendation for the QFN packages you can found it on the application note AN4530
http://www.freescale.com/files/sensors/doc/app_note/AN4530.pdf
have a good day