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AMC7823 temp sensor vs. max module temp

Hello,

Could you inform about suggested difference beetween AMC7823 temp sensor measuring results and temperature of rest module elements in conduction cooling mode. In other words, what is AMC7823 temp sensor temperature value at maximum module industrial range (+85C).


BR&Thanks,
Serge

This topic is being closed because the issue is considered as resolved by 4DSP. Feel free to create a new topic for any further inquiries.
Hello Serge,


We have verified some FMC30RF modules on VC707 and did not notify and of the behavior we saw when testing your modules on the ML605. I guess there is still a hardware issue with #145. Is it OK with you to send it back, so we can investigate this more? Please let me know and I will generate an RMA number for the return.


Best Regards,
Peter
Hello Serge,


We could reproduce the issue and repair the issue on ML605, but did not verify on VC707. Does #147, or other FMC30RF work on both platforms for you? On our side we can see what we can reproduce on VC707.


Thanks,
Peter
Hello Peter,

Sorry for delay, I didn't look at forum at all and waited for any additional info by email.

About #147 - we have seen once on this module similar mailfunction as #145,  then it starts to work normal.

We got repaired modules - #145 still shows  mailfunction with VC707 (VADJ=1.8V), but works well with ML605 (VADJ=2.5V).
Please see attached reports.

BR, Serge

Serge,


What is the reason for also returning FMC30RF-0147?
We looked at the boards and could reproduce your problem on FMC30RF-0145, but not on FMC30RF-0147.


I believe the temperature behavior on FMC30RF-0147 looks pretty normal, see attached. We cooled the device and let it heat up while logging the temperature every second.


Peter
Serge,


I cannot think of anything else. It looks like you are using our reference design and since the voltage reading comes out fine, I do not expect an issue with the communication interface. The temperature monitoring is internal in the AMC7823 device, so I can only assume a bad device. Please let me know if you plan to ship it back.


Thank you,
Peter
Hello Peter,

Could you offer additional test (or important conditions for done test) for this module to exclude possibility of any wrong condition of my test (results presented on this forum topic January 18, 2014)?

BR&Thanks,
Serge
Hello Serge,


Could you let me know if you are planning to return the board to 4DSP?


Peter
Hello Serge,


Apologies for the delay. FMC30RF-0145 is still under warranty. I issued an RMA. Please fill out attached form and include this when shipping the hardware back to us. The RMA number is 14012103.


Best Regards,
Peter
Hello Peter,

Thanks for channel 3 explanation.

About #0145:
I run test by attached .cmd and got 30 min log with temperature results (please attached too). Temp results is unacceptable noisy! Test looks as on photo. Others modules we have show temp quite correctly in same test .

TI support said that typically error for Vref=1.25V should be in 4C range:
http://e2e.ti.com/support/data_converters/precision_data_converters/f/73/p/315339/1097585.aspx#1097585


Could you remember about 4DSP warranty support process for #0145?

BR&Thanks,
Serge
Hello Serge,


I have no idea what is causing the temperature reading to change. There is no external circuitry involved, so it could be the AMC7823 specifications itself.


I checked our User Manual and unfortunately we have listed the wrong voltages.
Channel 3 should be 4.0V (same formula)
[font=Verdana]Channel 4 should be 5.0V (same formula)[/font]

[font=Verdana]I apologize for the confusion, the reference design output is listing the voltages correctly in the order from channel 0 to 7.[/font]

[font=Verdana]Best Regards,[/font]
[font=Verdana]Peter[/font]
Hello Peter,

I found big difference (noise like, 5C peak-to-peak) beetween sequence of AMC7823 temp results when use 202_ml605_fmc30rf.bit with Fmc30RFApp.exe. AMC7823 voltage results look more stable.
Could you explain this noise? How to read temperature with max precision?

Moreover, module #KDJC000145 has susperious jumping temperature result.
Please see attached log of sequence mesurements made during several seconds.


P.S. Could you  approve information in table 4 on page 13 of FMC30RF User Manual r1.1 October 2012 about
Channel 3 1.8V Digital? I found on this channel value near 4V.




BR&Thanks,
Serge

Hello Serge,


This is also information we do not have available. We offer 3D models of our boards to customers free of charge. This allows for implementation of best case cooling where the cooling frame also connects to the top surface of the most power consuming parts.


Best Regards,
Peter
Hello Peter,

Thanks for reply.
Could you provide suggested/measured effectiveness of conduction cooled ribs (e.g. thermal resistance of module via this ribs)?

BR&Thanks,
Serge
Hi Serge,


We do not have any data available for that.


Best Regards,
Peter