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How and where to connect an EPAD pin in Kicad6

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newtekuser:
As I understand an EPAD (exposed PAD) is a thermal area used for heat-sinking an IC. My DRV8825 IC has one, but I don't know how it needs to be connected. By default, the footprint I got from UltraLibrarian designates the EPAD pin as "unspecified".
I'd like to connect it to the ground plane (bottom layer) using VIAs:
In eschema I tried leaving this pin unconnected, then dropped a few dozen vias on it in PCB layout. Not sure if that's the way to go. If I connect this pin to GND in schema I get all sort of errors in DRC.

Either way I also get these mysterious errors in PCB layout DRC (attached) about clearances within the pad itself. Don't know what it wants from me. Any ideas?

JoeyG:
This is a common question to many  silicon manufacturers.

You are best to ask the manufacturer

Many data sheets have no electrical connection and some ( not all)  say connect to Vss.

Hence to be 100% sure contact the manufacturer.

selcuk:
PPAD is connected to the ground in the datasheet. If you have this pin (29) on the schematic symbol, connect it to the ground. Then connect it to ground in the layout as well. You may consider it as a regular ground pin.

I don't have that footprint, but I've attached a sample footprint having a center pad.

newtekuser:

--- Quote from: selcuk on January 31, 2024, 07:07:30 am ---PPAD is connected to the ground in the datasheet. If you have this pin (29) on the schematic symbol, connect it to the ground. Then connect it to ground in the layout as well. You may consider it as a regular ground pin.

I don't have that footprint, but I've attached a sample footprint having a center pad.

--- End quote ---


Done, dropped a few VIAs on it to GND. About the DRC error in my original screenshot, is it safe to ignore?

selcuk:
No need to ignore it. I think there is a pad somewhere in the picture not numbered as 29. Make sure all active pads in that area (smd or through hole) have the number 29. When you connect the pin to gnd in the schematic, all of them will be grounded in the layout. You won't get DRC error in that way.

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