SN74AXC4T774: Thermal PAD difference

Roey Tal

Prodigy 135 points

Part Number: SN74AXC4T774

Hi Team

Can you explain why there is diiference between the UQFN and WQFN and only the WQFN has thermal pad?

Is there any frequency restrictions between components?

Regards,

Roey

over 2 years ago

0 Michael Ikwuyum over 2 years ago

TI__Guru 50886 points

Hi Roey,

Yes, there is a difference (also highlighted in the datasheet) because they are both different package options. Are you looking for UQFN and WQFN package options that are the same? Also, by frequency restrictions are you referring to the data rates? If so, then no; as the package type do not impact the functionality.

Also see [FAQ] Where do I connect the thermal pad of the logic QFN devices? and the referenced link for all packages that TI uses (and their differences):http://www.ti.com/support-packaging/packaging-tools/find-packages.html, thanks.

Best Regards,

Michael.

0 Roey Tal over 2 years ago

Prodigy 135 points

Thanks for the answer

I assume that the pad in the WQFN is for thermal relief

You mention that baud rate of the component does not change with package

So, the same power can develop on each one of the packages

So why to choose WQFN over UQFN? I mean why do you need the thermal pad anyway?

Does the WQFN getting hotter than the UQFN?

0 Michael Ikwuyum over 2 years ago in reply to Roey Tal

TI__Guru 50886 points

Hi Roey,

The dimensions and thermals are the main differences between both packages.

Please help refer to 6.4 of the data sheet for the thermal differences and [FAQ] Where do I find maximum power dissipation for a device? to help further clarify the power that can develop on each of the packages, thanks.

Best Regards,

Michael.

Logic

Logic forum

SN74AXC4T774: Thermal PAD difference