Uc300eth-5lpt overheating precautions

[jtar40]

Hey there everybody!!
I have a uc300eth-5lpt controller board. I've been doing a lot of research on it to be careful of not burning the chip. But I reached a question which I don't really know the answer to. Would there be anyone who knows how hot the uc300eth ic can get before it may become too hot? And what I mean by too hot is that the ic may become disfunctional or burn??


Thanks in advance!!!!


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[Ger21]

It shouldn't get hot at all. Is yours getting hot?

[jtar40]

I'm not really sure what's considered hot. When I plug it in (and Don't run anything) it's ic temperature continuously increases and I stopped it at 102°f (38.9°c). I know that's a safe number but I just want to be extremely careful because I don't want it to keep increasing and burn out the chip (considering that I don't know what temperature is considered safe). That's why I asked because I don't want to let it continue climbing in temperature until it's too late. But does anyone know if there's a safe temperature range for the uc300eth ic?? I couldn't find one in the manual....
Thanks
Justin

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[the great waldo]

Ask the guys on the uccnc forum http://forum.cncdrive.com/viewforum.php?f=2
Balasz will give you the answer.
Cheers
Andrew

[Doddy]

For commercial grade semis then you can expect an operating temperature of the silicon die of 85C, and there was a general rule of thumb when I was a lad that you halved the MTBF for every rise of 10C above this. Note, I'm talking die temperature and that is not the same as the package temperature (which will likely be less, depending on environment). Of course what should be measured is the temperature increase - if your ambient air temp is 39C then a die temperature of 40C is less of a concern than an ambient of 10C.

BUT, the question you should be asking is more why the micro controller is getting warm. Actually, 40C isn't particularly hot, though I cannot recall ever fingering my UC300eth whilst in operation - I don't think it gets particularly warm (and I'm not about to strip it down to check). What you seem to be indicating is that the temperature of yours rises quickly and you expect it to continue to rise if not de-powered. That would concern me a lot. Is this a new device?, do you know if it is functioning correctly?, have you tried this with nothing connected to the input/outputs from the board?

[Ger21]

I agree with Doddy.
I've never checked mine either, but I don't think it gets hot at all, just a little warm?
I'd consider 100°F to be warm, not hot at all.

[john swift]

After a quick look at photos of the uc300eth motoin controller board and
5lpt mother board board
It does not look like all of the uc300eth outputs are buffered
26109
26110

How are you connecting your stepper drivers to the 5lpt mother board board ?

If for example your using a breakout board with 74245 octal buffers
to connect the uc300eth to the stepper driver inputs
the load on the uc300eth outputs will be reduced and have a measure of protection

Reducing the load on the uc300eth will also help to reduce the heating of the linear 3.3V regulator
26111

John

[Doddy]

John, from last time I trawled the main board there are octal buffers driving each output to 5v logic levels. Each input is fed through a resistive voltage divided into the Microcontroller daughter card.

The 3v3 reg only powers the micro controller, with the buffer logic driven from the off board 5V supply

... though it’s been a while since I looked

[john swift]

Hi Doddy

not sure we are looking at the same board

the picture of the 5LPT-UC300 Motherboard
26112
I am looking at has seven 14 pin IC's

possibly non inverting hex buffers ? (74HC365E ?)
[ with 6 inputs , 6 outputs & 2 supply pins ]

or 7414 inverting hex buffer found on some breakout boards

octal buffers like the 74245 have 20 pins -
8 inputs, 8 outputs, 2 supply (Vcc & Gnd) , 1 enable & 1 bi direction data control

John

PS

Just downloaded the UC300ETH manual (again) and see

2 ports have 12 outputs (like a PC printer port ) and the other
3 ports have only have 4 outputs

giving you a total of 36 digital outputs
so 7 hex buffers gives you 42 digital buffers to be used to buffer the micro controller

[Doddy]

Your right, can’t rember device specifics but confident they were Schmidt trigger buffers or inverters.

Was a UC300ETH and all outputs buffered

For reference, was looking to develop my own buffer/bob motherboard but lost interest