RθJA (thermal resistance, junction-to-ambient) value required for intrisic safety certification

[Amarotica]

Hey there, we are currently going through regulatory testing for a hazloc product. Our product includes an nRF52805 which is used for BLE provisioning and debugging of the system. Our certification partner requires the RθJA value for the nRF52805 IC to continue with certification.

We have been unable to find the RθJA in Nordic's documentation - are we overlooking something?

To be clear, it is quite obvious that this IC shouldn't have thermal issues/safety issues, but intrisic safety certifications are extremely strict and need the actual data nonetheless.

Thanks in advance!

[Asbjørn]

Hello Taylor,

We can't share the report itself as it's a product of our package vendor.

For the QFN version of the nRF52805 we have thermal junction number (RθJA) at 27.01°C/W.

For the WLCSP we haven't got a specific number for the nRF52805, but for the nRF52832, which is slightly larger. So the nRF52832 has a junction number at 40.86°C/W. For the nRF52805 WLCSP the number will be slightly higher, estimated around 45°C/W. 

Best regards

Asbjørn

[Amarotica]

Thank you Asbjørn this is great info! I've passed it along to our testing partners and will ping back here if we have any more questions.

[jk1]

 Asbjørn I'm in the exact same boat. Any chance you guys can get the nRF52805 WLCSP °C/W number and can add that to the product specification?  

And the irony is if it even said 200°C/W we'd be pass, since there's no way this will fail compared to other items!  But without just about *any* number it's a no go.  

[Asbjørn]

Hi Jonathan,

We haven't got more details than what I described below here for now. I understand you need some more specific details and I'd encourage you to contact our sales organization where you are and convey the message. We have limited availability to request specification details, even on behalf of customers from tech support point of view.

BR

Asbjørn