Electronic – Unrecognized IC Package Style


I'm implementing the NXP TDA19988 HDMI transmitter IC in one of my projects and I am currently in the PCB design stage. I am building my component library and when I came across this part I wasn't sure how to proceed. I am familiar with standard 64-pin QFNs. However, this one seems to have additional "pads" on the bottom, besides the normal electrical connections:

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Unless I overlooked it, they do not seem to be mentioned in the datasheet. Are these simply extensions of the ground plane/pad on the bottom of the IC? My suspicion is that they are acting as a reference plane for the internal bond wires leading to the electrical pads to provide controlled-impedance, in which case I assume I need to have them connected to ground. Is there a specific land pattern that I should follow for these sorts of packages? The land pattern I have is the SOT804-2 (vs. the SOT804-4 I'm really looking for) and can be found on page 3 of this document:



Since apparently I wasn't being clear enough with my question, here it is in a concise, readable format:

Where can I find the recommended land pattern for the SOT802-4 64-pin HVQFN package used for this device?

Best Answer

This might be the drawing for SOT804-4, which you are looking for. The land pattern is on p.3 .
The second row isn't soldered to the board, if I'm reading the drawing correctly.

I'm guessing, each oblique pad in the second row is connected to the pin on the outer row. So, the second row would be signals, not all grounds. If you have the an IC in your hands, you could check continuity.

p.s. I wonder what's the rationale for this odd QFN, and why a typical QFN didn't cut it.