Atmel library: SMD symbols lack pin for center pad

[kicad]

Atmel library: SMD symbols lack pin for center pad

This is a contentious issue.

1. As Atmel wrote in his DS: "NOTE: Bottom pad should be soldered to ground.". Neither "must be", nor "have to be" only "should be". IMO this is a suggestion only.
2. Bottom pad hasn't pad number nor name, so how to represent something that "electrically doesn't exist"?
3. The QFN bottom pad can be connected to the GND net through static assignment in footprint.

[madworm]

1: maybe
2: Give it a number that is guaranteed to be unused ( last normal pad # + 1 - e.g. "33" for QFN32 ), as is done in [SMD_Packages:QFN32]. Some of these 'official' footprints are named e.g. "QFN48" (no pad) or "QFN48+1" (with pad). What is the harm of representing the extra pad in the symbol?
3: Yes, I can assign a net name. But every time I re-read the netlist that assignment goes away.

1. OK. Let the designer decide. When atmel.lib will be adjusted to KLC rules I will try to suggest to include bottom pad.
2. QFN-xx-1EP footprints has this pad numbered as n+1.
3. Like in 1. Let the designer decide, when we give him a choice.