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Pzkrat's avatar
Pzkrat
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6 years ago

CYCLONE 10GX remote temperature sensing

Hi all,

started to use Cyclone 10GX remote temperature sensing diode. However, see quite an offset compared to internal sensing (I am aware of the +- 5°C tolerance, however this time it seems that the internal is closer to the truth). Using TMP451 from TI as a remote sense. Now:

-When default ideality factor 1.008 is used, these two vary about 1deg C. However, if n=1.03 (value suggested by datasheet) is programmed into the TMP451 device the difference is about -8deg C

-The remote value readout is stable, no significant jumps, so probably no noise issues. Traces are very short, less than 9 mm, no obvious dirty signal crossing

-I found out that TMP451 device actually uses 3 different currents (120uA, 45uA, 7.5uA) to readout, which might be out of the part spec? (unfortunately I did not came across chip that would satisfy all the requirements and where all the parameters were in the recommended region)

-There seem to be no noise on the TMP451 supply input

Question is:

-Is there any recommended part for remote sensing?

-The diode ideality factor. I understand that this is not something calibrated, but how reliable is the datasheet value? Is this something that varies a lot between chips or is this more or less process dependent?

Thanks for any ideas.

6 Replies

  • Pzkrat's avatar
    Pzkrat
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    5 years ago

    Thanks very much for reply. The TMP512 parameters are very similar to TMP451, including the default diode ideality factor. While going through the max 10 code we could not find any reference to changing it to Cyclone 10GX datasheet suggested 1.03.

    While browsing other documentation I saw that Stratix datasheet actually suggests that for three current measurement method, some of the sensors should have ideality factor 1.006 while for two current method the 1.03 should be used.

    Could you please confirm:

    1) Do we understand correctly, that on the cyclone 10 Dev kit, the TMP512 default ideality factor used?

    2) the Ideality factor in Cyclone 10 datasheet refers to two current measurement method and different value should be used for other measurements method?

    Thanks

    (pasting the reference from stratix 10 datasheet)

  • Rahul_S_Intel1's avatar
    Rahul_S_Intel1
    Icon for Frequent Contributor rankFrequent Contributor
    5 years ago

    Hi ,

    To be precise, I do not have internal data to confirm the below.

    that on the cyclone 10 Dev kit, the TMP512 default ideality factor used?

    For Cylone 10 GX , I am request to follow the data sheet , because the S10 is a multi die device so that characterization for the C10 GX is different

  • Pzkrat's avatar
    Pzkrat
    Icon for New Contributor rankNew Contributor
    5 years ago

    Ok Thanks. Would be great if the ideality factor used on the dev kit could be confirmed, as it seems that the datasheet might not be accurate.