User's Manual

12
Atmel AVR2080
8479A-AVR-01/12
Figure 5-3. Board layout – XTAL section.
When designing applications for very harsh environments, for example where the
radio transceiver is close to mains power lines and burst and surge requirements
already dictate special provisions in the design, the above reference crystal design
might not work well. In this case, the reference crystal ground is to be directly
connected to top and bottom layers.
5.3 PCB – analog GND routing
Analog ground pins (3, 6, 27, 30, 31, and 32) and pin 7 are to be routed to the paddle
underneath the IC. The trace width has to be similar to the pad width when
connecting the pads, and increase, if possible, some distance from the pad.
Figure 5-4. Board layout – transceiver GND.
3
12
16
18 21
27
30
31
32
7 6