HDC1000 RH-offset & recover-times

I have the same problem. I have 1000 boards that read 20% lower than the prior revision. I've tried everything including re-hydration process. I'm to ship in one week and don't know what to do... The manufacturing house was very careful to follow all the recommendations. Plus, the prior rev s worked fine after going through the same reflow process.

BTW, I ran very thorough testing over the weekend with both Rev B and Rev C boards as well as a 3rd party logger. All boards running same software, same conditions, all Rev C read 20% low.

Also purchased a batch of 5 from Digi-Key on 11-4-15 (296-38440-1-ND) with the same issue.

We have the same problem, our old boards worked and were using the HDC1000 and with the same firmware the HDC1000 are reading correctly and the new boards with the HDC1008 are 15% to 20% below the reference and the previous boards. I did try to configure the boards to 11bit temp and 8bit RH as well as enable the read both temp and RH in one (config register 0x02 = 0x1600). We are still trying to see if anything can be done in terms of firmware however we were able to get the full range (0 to 96%) of RH which means adding a simple offset won't fly. Got the batch from Digikey, sometime on Aug, the chip marking is 58F GK.

I tried another run of boards with the same batch of sensors.  This time I lowered the reflow temp down to 200C peak with SN63/37.  Even at a much lower reflow peak I am seeing humidity readings about 18% too low.

Hi All

As noted in their datasheets, devices HDC1000YPAR, HDC1000YPAT, HDC1008YPAR, HDC1008YPAT, HDC1050DMBR, and HDC1050DMBT may exhibit RH measurement shift. As described in the datasheet section 9.3.2, the RH sensing element goes through a settling process with exposure to time, temperature and humidity. Material before 1527 could settle to an offset of +15%. The typical accuracy (RHACC) range for these devices remains unchanged and not guaranteed. We have recently reduced the potential measurement shift through electrically adjusting these materials and are offering to exchange newer devices (datecode 1527 or after) for older devices (datecode before 1527).

Options for materials:

• Datecode before 1527
- Account for RH measurement shift in system performance, or
- Material can be returned to TI for replacement

• Datecode 1527 or after
- To accelerate the settling process after soldering, refer to the datasheet for recommended hydration (85C, 85RH, 12hr) per section 9.3.2.

TI will be introducing the HDC1080 replacement option which does not exhibit this settling behavior and does not require rehydration. The HDC1080 is a drop-in replacement for the HDC1050 and is software- and function-compatible with the HDC1000, HDC1008, and HDC1050.

Regards
Massimo

Massimo - Thanks for jumping in. I believe you mean -15% offset? Those of us with problems in this thread as seeing negative offsets.

As for rehydration, I assume this doesn't work on the older datecode parts?

I purchased a Digi-Reel that is D/C :Jul-2015 L/C 5283412em5. I have some pieces left and some pieces are on boards (that are now useless). How do I go about getting replacements? Do you have a direct email or phone number?

Thanks,
Josh

I was looking for the datecode on the HDC1000, but there I find only:

5AJ  E4

instead of something like 1524.

How I get the datecode?

Regards,

Rolf

I have three lots of sensors marked:

58F
GK

514
GK

5AJ
E4

The lot 58F is after the 1527 datecode, but this is the main lot I have had issues with.  

How do I get replacements?

Massimo,
I have 2000 sensors, HDC1008, first 30 exhibited the same 15% offset. This is not acceptable for our device going forward.
I changed the design to accommodate HDC 1080. I need to return 2000 HDC1008 chips purchased through Avnet.
Please provide me with your internal reference number for this case so I can deal with Avnet and return the parts.
Many Thanks,
Ondrej

Hello Ondrej

Please ask to your Avnet representative to contact me directly.

Regards

Massimo