CC2538-CC2592EM-RD: 38MHz crystal or TCXO recommendations for outdoor extreme temp application

rperezti

My customer is developing a system based on CC2538-CC2592EM-RD. The system will be exposed to extreme temperatures (-40C to 50C). We are looking for crystal or TCXO recommendations that will maintain high accuracy under these conditions.

over 4 years ago

0 TER over 4 years ago

TI__Guru**** 317180 points

Have you checked the xtals that are used in the BOM for http://www.ti.com/tool/CC2538-CC2592EM-RD?

Note that most commercial components are rated from -40 to 85 degrees C. You are not stating what "high accuracy" mean.

0 rperezti over 4 years ago in reply to TER

TI__Genius 12185 points

Thanks for the reply. The customer is making several H/W changes to improve RF robustness. They are looking for 32MHz clock options that offer lower than 20ppm stability / 10ppm tolerance and that spec the frequency down to -40C. The crystal used in the CC2538-CC2592 reference design only specifies the frequency tolerance down to -20C. The customer is willing to move to a TCXO and they are asking if TI has any recommendations.

I just noticed that the title incorrectly states 38MHz. This was a typo as the design actually requires 32MHz. I am unable to edit the title.

0 TER over 4 years ago in reply to rperezti

TI__Guru**** 317180 points

For some reason I assumed that the xtal used in the ref design had the same temp spec as the chip.

I could not find any other recommendations than the one used in the ref design. I would recommend contacting the xtal manufacturers directly and provide them with the wanted spec, including the spec that is given in the "32-MHz Crystal Oscillator" table in the datasheet. It also look like it exist different variants of the xtal used in the EVM BOM with larger temp range: https://www.digikey.de/product-detail/en/epson/FA-128-32.0000MF20X-K5/SER4079TR-ND/5209190 (I haven't checked all parameters towards the datasheet. I just used the filtering to come up with some options)

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CC2538-CC2592EM-RD: 38MHz crystal or TCXO recommendations for outdoor extreme temp application