Other Parts Discussed in Thread: DRV8876
Tool/software:
I have now gotten many different responses on this topic and it is still not clear to me. The TI PowerPAD guide (PowerPAD (TM) Made Easy (Rev. B)) seems to recommend connecting the PowerPad to the ground plane. However, on the DRV103 datasheet it says
"Although the metal pad of the PowerPAD
SO-8 (H) package is electrically connected to ground (pin 4), no current should flow in this pad. Do NOT use the exposed metal pad as a power ground connection or erratic operation will result. For lowest overall thermal resistance, it is best to solder the PowerPAD directly to a circuit board, as illustrated in Figure 13. Increasing the “heat sink” copper area improves heat dissipation."
Which indicates that it should be isolated from ground. This was confirmed by answers on the threads "DRV103: Connecting ground to PowerPAD" and "DRV103: Connecting ground to PowerPAD Revisited". However, now I am seeing other answers recommending that it IS good practice to connect it to ground (see "DRV103: DRV103 Powerpad connection to ground").
In my design, I need to connect the PowerPAD to a ground plane for heat dissipation. However, I am concerned about the stated "erratic operation" that could occur. Obviously, the chip dedicated ground connection is ALSO connected to ground, but there is no way to guarentee that no current flows in the pad if it is connected to ground as well. Are these new answers based on an updated understanding of the device, or are they incorrect? Is there a method of connecting the pad to ground WITHOUT allowing current to flow that I am missing?
