Problems about spectrum anomaly

[WenChao]

Hi，the NXP team,

We're using the S32R274 and the TEF8102 to design radars.Our reference design is the project ‘Cocoon2_ATB-NXP’ by RFbeam Microwave GmbH,23.03.2018.Then we found some problems about spectrum anomaly.

When the temperature detected internally reached about 80℃,the spectrum we received will become very strange,as pic no.2 showed.You can compared it with the normal spectrum pic no.1.

When we found this phenomenon was related to temprature,we have optimized the heat disspation of TEF8102,but the problem still happend when the temperature reached about 80℃.

Please help us with this problem,anything would be helpful.Thanks!

[petervlna]

Hello,

I was talking with AFE expert but the description is too general.

His feedback was that this can have multiple causes, but he would not expect temperature dependency.

I can see some errata on temperature in TEF810x errata sheet, did you check them?

best regards,

Peter

[WenChao]

Hi,Peter， Thank you for your advice.I've checked the errata sheet,but I didn't found anything samilar. And there's anither phenomenon about this problem.When we're using all the three antennas to transmit chirps,the problem will appearsin 80℃,But when we only use two antennas to do the same thing,no matter which antenna we don't use,we didn't found the problem even in 86℃. Now we don't know how to analyse this problem,We've tried to give all the power we needed from DC POWER SUPPLY to verify if this thing is coming from the FS8410,including 2V3 and LDO3V3 for TEF8102,3V3 and 1V25 for S32R274,LDO5V and 3V3 for TJA1059,12V for TJA1101NH.But there's another problem happened,The TEF8102 can't be initialized and this will lead to system reset. Our FAE suggested us to optimize the heat dissipation,but I think this can't solve the real problem.If there's anything we missed,please let me know,anything would be helpful. BR, WEN CHAO