Thermal operating range of the Ethernet/USB controller on the Balena Fin


Hey, I ordered and received a Balena Fin developer kit the other week from the store. There’s what’s looks like a revision sticker saying “F 35/18” on the back on the board I received.

We’re looking to build an outdoor-climate-proof solution, so the combination of the Balena Fin and caught my eye as a quick way to market for the first iteration of our product, given that the Balena Fin datasheet on page 11 specifies an operating temperature range of -25C ~ 70C.

The board uses the SMSC/Microchip LAN9514 chip as a combined USB hub and Ethernet 10/100 controller/PHY. When inspecting the board, I noticed that it had the LAN9514-JZX variant, and not the LAN9514i-JZX one.

The two variants have these operating temperature specs:

  • LAN9514-JZX: Commercial temperature range: 0C ~ 70C
  • LAN9514i-JZX: Industrial temperature range: -40C ~ 85C

So, it seems like at least on the board I received, this chip was of the commercial temperature range kind, and thus rated at a narrower temperature range than the specified Balena Fin temperature range.

For reference, here’s a close-up of the board I received:

The relevant chip is in the middle of the photo, and as you can see, it’s the LAN9514-JZX variant. (Not LAN9515i-JZX)

So,, what you can make of this? Misunderstanding on my part? Design mistake? Logistics/manufacturing mishap?

Either way, I hope we can eventually end up with a Balena Fin that’s designed/manufactured to work in cold temps.


Also: This post was at first not allowed because it contained “more than 2 links”. As I kept removing the large number of useful links that I had carefully crafted, I was eventually “flagged” and my account was temporarily suspended.

Even now, I can’t edit the post; when I try to save the edits I’m met with the same “more than 2 links” message. I realize you have spam to fight, but…


Hey @jschon, thank you for spending the time to create such a thorough report for us. I’ve increased the number of links allowed for new members to 5 but note your trust level is now increased so you’re not subject to that anymore anyway.

Our engineers are looking into this for you and will be back with an answer as soon as possible.


Hi again @chrisys,

It’s been about a week. Any progress on your side?

Do we need to re-evaluate our efforts to design a solution around Balena/Balena Fin since we require cold/wide range temperature capabilities?

Just so we’re clear, here is the the part of the datasheet I was referring to (


Hi @jschon, we’re in the process of working out a way forward on this, and waiting for feedback from component and testing suppliers. I don’t have any more information to pass on at this stage but at this point I expect to hear back next week. Thank you for following up.


Hi again,

Thanks for taking this concern seriously. Any updates to share?


hey @jschon no specific update at the moment, but checking with the team, and should get back to you once we have anything new!


Hi @jschon, thanks for your patience whilst we’ve been investigating this.

Your observations are correct, the temperature range of the LAN9514 variant we use is narrower than the one stated on the balenaFin data sheet. That is also the case for the RJ45 connector (0 to 70 Celsius). Unfortunately, there is no much we can do for the v1.0.0 of the Fin (which is the one you got and the one we currently have on store. An errata will be issued in the following 24 hours along with an updated data sheet.
We spent much of these past weeks looking for a solution and the good news is that we are very confident that the next version (coming early 2019) will have a working temperature range of -20 to 70 Celsius.
We will keep you updated on the development of the next version.



It’s really good to hear that you are committed to fixing this issue!

I’m surprised by the RJ45 connector also being affected - I guess the plastic gets too brittle at low temperatures? As long as you don’t plug in new cables at -20C it’s probably fine though.

We’ve continued our development with a Balena-based solution, considering a regular Raspberry Pi 3B+ combined with a thermostat-activated electric heater inside the outdoor enclosure.

We’re nearing the coldest part of the year here in Sweden (jan-mar). I’m planning to do some real-world outdoor testing of our current solution soon - let me know if you want a beta tester of that new HW revision. :slight_smile:


@jschon components are not necessarily affected. More often than not, manufacturers avoid testing components under extreme conditions because of the high cost. If there weren’t any tests performed at that temperature, the component cannot be guaranteed to work.

I’m glad you were able to keep working with the balenaFin. We’ll keep you updated on the developments of the new iteration. We are already testing an early production sample.