Mux I2C design layout.?

DickCappels

Joined Aug 21, 2008
10,152
Without an explanation of what each pin in each of the connectors does with respect to your mux chip, other than feedback that it looks real pretty. I2C is pretty from worry about creepage distance and things like that. You don't have any long runs so I would worry about things like cross-talk (maybe in the cable there would be a long run) and ringing.
 

Thread Starter

andriasm

Joined Aug 2, 2022
25
Without an explanation of what each pin in each of the connectors does with respect to your mux chip, other than feedback that it looks real pretty. I2C is pretty from worry about creepage distance and things like that. You don't have any long runs so I would worry about things like cross-talk (maybe in the cable there would be a long run) and ringing.
Thank you for your feedback. I will design on the board the description of each pins of the connector.
 

Jon Chandler

Joined Jun 12, 2008
1,029
You have no power connection to Vcc (pin 24) on the mux chip.

On channel 4, you have the clock and data lines from different channels from the mux chip.

Add a 100 nF bypass capacitor between Vcc and ground close to the mux chip. Always a good idea.
 

dendad

Joined Feb 20, 2016
4,452
Add a 100 nF bypass capacitor between Vcc and ground close to the mux chip. Always a good idea.
I agree! For some reason, bypass caps are often left off as if they are not important. A good clean power supply is the foundation on good electronics. I woul add a 10uF Tant as well as the 100nF ceramic cap because this looks like it will be plugged into the main board some distance away.
 

Jon Chandler

Joined Jun 12, 2008
1,029
One thing I have found convenient...

When positioning board mounting holes, it's easy to forget the clearance needed around the hole for a screw head, nut or spacer, and the space needed for a nut driver to tighten a nut or spacer. I have created a "mounting hole" footprint for 3mm/4-40 hardware that has the hole and in the board document layer shows the outline of a nut and a circle showing the nut driver diameter. 3mm/4-40 are close enough in size that one footprint works for either.

Because the pattern is in the document layer, it shows up while you're laying out the board but not in the silkscreen layer on the finished board.

SmartSelect_20220202-154610_Edge.jpg
 
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