Comments on Assembly challenges for shared pad between mounting hole and resistor
Parent
Assembly challenges for shared pad between mounting hole and resistor
Hi,
I was watching Many EMC Tips to Help You Design Better PCB Boards (with Keith Armstrong) and at 1:01:30 timestamp he talks about bonding reference plane to chassis and emphasizes that the connection has to be low-impedance and very close:
My question is the practicality of doing this, how would the assembly process look on the left side pad of the resistor? I imagine the paste would flow all over the mounting hole pad. Here is what I had in mind instead:
Please let me know what you think about these two options and any experience you have regarding this!
Post
Here's how I usually lay out optional grounding through a mounting hole. The connections are wide copper pours which reduces the connection inductance. Multiple vias to GND also reduce inductance.
One may have insights about the EMC, but one doesn't really know until one tests. Optional earth ground is useful in prototype boards. Furthermore, the EMI situation may change because the way your device is used may change (normal turn of events for lab equipment, for example).
The R201 and C201 footprints are 0603, and they have a finite inductance. I haven't got data up to what frequency range this connection is effective against EMC. If I needed to make an ad hoc low inductance connection there, I would solder a wide strip of braid or copper tape across R201 and C201.
p.s. Another way to create a mounting hole with a disconnectable chassis ground. If your mounting hole works with a standoff, sometimes you have a choice if the standoff is plastic or metal.
0 comment threads