What's the QG8's "Exposed Die Attach Pad"?

[Wings]

I'm starting to lay out a board using the 9(S)08QG8 in the QFN package. I won't have one of these to hold in my hands for another few weeks, and there is something in the datasheet that I could use some help with. In the mechanical outline drawings it shows a large area under the chip noted as "exposed die attach pad", and my question is, is this area metallic? If so, should it be soldered to Vss? Left unconnected?

Thanks for an answer.

[irob]

I've just built up some boards with these MCUs, QFN16. And I asked the same question as the datasheet doesn't have any direct info.

Those pins are indeed metallic but the (somewhat illegible) word I got from Freescale support was:

In reply to your Service Request SR 1-261344051 (see details below):

It is not a Pin called 17 pin .But the pad is used for release heat of the MCU .So it need not to connect to ground .

Should you need to contact us with regard to this message, please see the notes below.

Best Regards,
Alan

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This message is in reply to the following service request:
SR Number: 1-261344051
Date Opened: 3/8/2006 09:44:09 AM
Subject: center tab on MC9S08QGxCFFE
Description:
I have the full datasheet but I can't find anywhere about this part's center tab. It's a QFN16 and I need to know if the center tab (pin 17) is connected to ground or not.
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Also see this thread.

[alex_spotw]

Hi:

I checked the datasheet and no information is to be found about the exposed die. My guess is that it needs to be connected to VSS. It is a metallic plate undernead the chip used normally for power dissipation.

Regards,

Alex