User's Manual

12 P412 User’s Manual & Data Sheet
Fig. 8: Hole sizes: Index table
The user must provide a sufficiently sized heat sink such that the temperatures of the board can be
kept below the maximum allowable temperature for the target deployment environment.
Most of the heat is generated by the AFE chip. There are two means by which this heat can be
extracted from the board. First, a heat sink can be placed directly in contact with the AFE. While
this will work, it should be noted that most of the heat generated by the AFE is transported to the
board through the BGA balls on the AFE. While heat can escape through the top of the chip, the
transfer characteristics of silicon are poor. Once the board begins to heat, the temperature of the RF
shield will rise. This offers the second opportunity to extract heat from the board. Because the RF
shield is tightly connected to the board ground plan, connecting the shield to the heat sink will greatly
increase the rate at which heat is transferred from the P412.
Figure 9 shows the mechanical dimensions for both the AFE and the RF Shield. Figure 10 shows a
notional heat sink strategy and calls out dimensions of relevant structures. Figure 11 shows relevant
clearances.