2: Description and Specifications
XPort Pro Integration Guide
11
Recommended PCB Layout
The hole pattern and mounting dimensions for the XPort Pro device server are shown
in the following drawing. For proper heat dissipation, it is recommended that the PCB
have approximately 1 square inch of copper attached to the shield tabs. The shield
tabs are an important source of heat sinking for the device.
The XPort Pro shield is considered “chassis ground” and should be separate from
“signal ground”. ESD near the XPort Pro at the panel opening will likely jump to the
shield.
We recommend using high voltage (~200V), low ESR, 0.01uF capacitors to connect
chassis ground to both signal ground and 3.3V. This will cause any voltage spike
from ESD to be imparted equally to both signal ground and 3.3V with no net voltage
increase between 3.3V and signal ground. For the highest level of ESD protection of
the XPort Pro, it is recommended that the shield not be directly connected to signal
GND. The metal shield fingers around the XPort Pro’s RJ45 should physically contact
the product housing when the housing is metal, or metallic coated.
The shield is also a heat sink for the internal 32-bit Processor. As in all heat sinking
applications, the more copper connected to the heat sink the better. Adding 1 inch
square inch of copper flood on the PCB is adequate to allow the XPort Pro to work up
to +85°C. If the application does not expect to see temperatures up to +85°C the
heat sink may be smaller than 1 square inch.
Figure 2-7. PCB Layout
