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Ethernet Shield is hot, Hot, HOT!


#1

I’ve been using the Arduino Ethernet Shield (with the reset pin mod) with a FEZ Domino for some time now and just today I noticed that the WizNet chip and voltage regulator on the Domino are heating up like a mother!

I don’t think it’s always been this way, as I surely would have burned the thing out, given the temperature…

…the only change made today was to go from the FEZ Beta Firmware with the baked in ethernet support to the final release. I’m not saying that caused it, it’s just the only change that’s been made recently…

Does anyone have any thoughts or experience regarding this issue? I’m at a bit of a loss…


#2

You’d be surprised about how much temp Vregs will handle…

Are you SURE this a new issue?


#3

Yeah…it’s way too hot to touch.

I’m thinking something must have accidentally been shorted out on the Ethernet shield today (it did see a greater-than-usual amount of hands-on time today)…

Though the power light and connection lights come up on the shield, it doesn’t look quite right…

Time to order a new one!


#4

Wiznet chips get hot. The Wiz forum is full of people asking that question, and the answer is always the same, integrated PHY gets hot… So maybe you do have a problem, or maybe it’s “normal”, YMMV. I’d still be comfortable that there’s some life in your shield yet, unless you know it has performed incorrectly?


#5

If something shorted, the shield wouldn’t work at all and the FEZ would constantly reset itself.


#6

The Wiznet Chipset gets relatively hot. this is normal.


#7

What is “hot, hot , hot”. If you can keep your finger on it for over 10 seconds and scream from pain then it is not hot :slight_smile:

No seriously, the wiznet chip tend to run warm but if it is hot to the touch then it is too hot.


#8

vregs tend to thermal shutdown between 105 and 120c, so if they are not that hot (hotter than boiling water) you’re fine. Humans can only stand relatively low temperatures. Even 50c can seem extremely hot, and 60c is burning for us. For silicon this isn’t great, but it will run for years at those sorts of temperatures.


#9

Well, it’s not just the WIZnet chip, but one of the voltage regulators on the FEZ also heats up to uncomfortably hot temperatures when the Ethernet shield is plugged in.

So I’m pretty sure I somehow accidentally shorted something on the Ethernet shield…

Two more should be on their way direct from TinyCLR today via FedEx overnight, so I’ll post back whether or not those run cooler.


#10

Again, if you shorted anything the USBizi would just go into an infinite cycle of resets and the shield wouldn’t work…

A short literally means that current is totally bypassing a necessary route and heading down an unintended return path. Not all electrical failures are shorts, and when a short occurs, most if not all of the circuit will fail.

Things don’t just short and cause components to heat up without any other side effects.

Do you have a thermocouple that will give you a precise reading of what temp the reg is running at? Make sure to measure on the Vreg’s heatsink, or the little tab opposite the 3 pins.


#11

[quote]Well, it’s not just the WIZnet chip, but one of the voltage regulators on the FEZ also heats up to uncomfortably hot temperatures when the Ethernet shield is plugged in.
[/quote]

Are you using an external power supply? If so what voltage is your power supply putting out? If it is > 9V or so than the voltage regulator will have to dissipate a lot of extra energy (as heat).


#12

Since you are using the Ethernet shield which consume up to 150mA, the regulator will need to dissipate more power.
I recommned that you use a 6-7.5 volt external power supply.