SMT2 Storage & Operating Temperatures

[bhfletcher]

The Digilent JTAG SMT2 module has conflicting temperature numbers in the specification. It lists a max storage temperature range of -20 to +60C and an operating temperature range of -40 to +85C. Which one is incorrect?

Here is a link to the specification:

https://reference.digilentinc.com/_media/jtag_smt2:jtag-smt2_rm.pdf

 

Thanks,

Bryan

[jpeyron]

Hi @bhfletcher,

All the the parts on the JTAG-SMT2 have an an operating temperature range of -40 to +85C which has been tested and verified with the complete product. For the max storage temperature rage we went with the smallest max storage temperature range of -20 to +60C which we got from the different parts datasheets.

thank you,

Jon

[bhfletcher]

So you're telling me that I can operate the device at a greater temperature range than I can store it? I have never seen any component that has a tighter storage temperature spec than operating temperature spec. Will you please check with engineering?

Thanks.

[jpeyron]

Hi @bhfletcher,

I have reached out to our design engineer about your question. They have left for the weekend so I would need expect an answer until early need week.

cheers,

Jon

[jpeyron]

Hi @bhfletcher,

Our design engineer has gotten back to me with a partial answer. They could not remember which part led them to originally limit the storage temperature to -20C to 60C. From the perspective of the components the storage temperature can be -55C to 125C. They are not sure about the PCB and are researching this. I will post here when I get more information.

thank you,

Jon

[Bianca]

Hi @bhfletcher,

If you are concerned that the operating temperature is wrong I can tell that it is correct. I personally tested the SMT2 in the -40; +85 range temperature and everything worked without a problem. 

Regarding the storage temperature, like Jon said, we take it from the lowest level component. I  checked them all but I couldn't find the one with -20 to +60. As for the PCB, it shouldn't have any issues. When we are guaranteeing a range it is said that it is functioning in normal parameters. For the PCB alone I will have to contact the factory but for the whole product the temperature is set at the component with the lowest range which from I found is -55 to 125 like Jon said. In this range you should not have issues.

Best regards,

Bianca

[bhfletcher]

Thank you! When will the SMT2 specification be updated?

Bryan

[jpeyron]

Hi @bhfletcher,

Thank you for checking in with this issue. We have not heard back from the manufacture and have reached out again. When we have their response we will update the specification for the SMT2.

cheers,

Jon

[jpeyron]

Hi @bhfletcher,

Our design engineer got back to me with the following response:

 

I had our CM do an in depth review of the entire JTAG-SMT2 assembly, which includes things beyond just the components (PCB, Red Glue, solder, etc). The spreadsheet they sent me shows that several components on the board have a more narrow storage temperature range and their operating temperature range. From the data we concluded that the actual storage temperature range should be -10C to 60C. The operating temperature range remains -40C to 85C, which is wider than the storage temperature. I realize that this seems odd, but I think it’s has to do with the way that component manufactures define “storage” vs “operating”. I believe the time spans for these ranges are significantly different, but don’t have any concrete definition.

 

In any case, -10C to 60C should be considered the storage temperature range for both the SMT2 and SMT2-NC.

 

thank you for your patience,

 

Jon