Teensy 4.1 custom carrier PCB with inverted Ethernet header?

[bjorn]

Designing a custom carrier PCB for a Teensy 4.1 + Ethernet project and want to sanity check a mechanical/electrical detail before I commit the layout.

My plan is:

• Teensy 4.1 mounted to the carrier PCB using female socket headers
• Ethernet PHY/RJ45 circuitry integrated directly onto the carrier PCB (so not using the standard Ethernet daughterboard PCB itself)
• Use the Teensy’s existing 6-pin Ethernet header pads to connect directly into a socket/header on the carrier PCB

To make this work cleanly, I’m considering mounting the 6-pin Ethernet header “upside down” relative to the usual orientation:

• insert the male header pins from the underside of the Teensy
• solder them from the top side
• pins then protrude downward beneath the Teensy into a socket on the carrier board

My assumption is that the Ethernet header holes on the Teensy are standard plated through holes, so soldering from the top side should still electrically connect correctly to the Teensy PCB traces/signals.

Does this sound valid, or is there any reason the Ethernet pads on the Teensy 4.1 would not behave like normal plated through pads/vias?

I’m also trying to work out the mechanical side of this:

• alignment of the Ethernet header relative to the two main Teensy header rows
• whether the header pins supplied with the Ethernet kit are actually long enough to reach a socket on the carrier PCB once the Teensy itself is socketed above the board

Curious whether anyone has done something similar with inverted headers or custom Teensy carrier boards, or if there are recommended header/socket combinations for this kind of stacked arrangement. Here's the ethernet header kit I was looking at, though I may end up buying the individual components minus the ethernet board and ribbon cable, if what I'm planning is feasible.

Ethernet Kit for Teensy 4.1

This kit has all the parts needed to connect to the Ethernet port on Teensy 4.1.

thepihut.com

 

[shawn]

PJRC Store

www.pjrc.com

"Pins & Socket for Teesny 4.1 Ethernet, 6 pins, 2 mm spacing"

 

[bjorn]

PJRC Store

www.pjrc.com

"Pins & Socket for Teesny 4.1 Ethernet, 6 pins, 2 mm spacing"

Perfect, exactly what I need thank you. I already found that the KiCad Teensy 4.1 footprint has the ethernet header in alignment so this should be straightforward

 

[PaulStoffregen]

alignment of the Ethernet header relative to the two main Teensy header rows

Here's the dimensions drawing from the Teensy 4.1 page (scroll down to Technical Info). The 6 pin header's center location is shown relative to the first pin on the top side.

whether the header pins supplied with the Ethernet kit are actually long enough to reach a socket on the carrier PCB once the Teensy itself is socketed above the board

If you use normal size sockets and headers, then you need this taller header and socket.

Curious whether anyone has done something similar with inverted headers or custom Teensy carrier boards

Yes, you can see a photo on the page for the taller header + socket. (also scroll down at that page for dimension drawings)

It's definitely been done many times before, from the sales of that taller header over the last 5 years.

 

[bjorn]

Here's the dimensions drawing from the Teensy 4.1 page (scroll down to Technical Info). The 6 pin header's center location is shown relative to the first pin on the top side.

If you use normal size sockets and headers, then you need this taller header and socket.

View attachment 39316



Yes, you can see a photo on the page for the taller header + socket. (also scroll down at that page for dimension drawings)

It's definitely been done many times before, from the sales of that taller header over the last 5 years.

Thank you, very useful information and great to have this confirmed. My carrier PCB is nearly ready, just have to replace the teensy footprint with headers, final checks against references then get a test print done

 

[bjorn]

Just trying to replace the Teensy footprint on my PCB with female socket headers. I changed the pad diameters to match those on the Teensy footprint and brought the courtyards in as close as I could but the courtyards still collide :/ I guess I need to parts with bodies that won't collide.

Never done this before, it's kinda stressful xD