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HDC1080 humidity settling time

Zhou Fang67
Expert 4250 points
Other Parts Discussed in Thread: HDC1080

Hi Expert,

I have checked several threads, it is said that HDC1080 can humidity result can settle right after power up.

My customer has developed 5 boards with HDC1080 on them. We found the humidity can only be settled to final accurate results after 120s.

e.g:

1. Power up the 2 boards with HDC1080 as reference, the humidity is 57%.

2. Power up the 3rd board, the initial humidity is 67%.

3. Waiting 2 minutes, the humidity decreased to 57%, kept stable.

They use the default register setting REG 0x02: 0x1000.

If there any thing can lead to slow response time?

Thanks a lot.

Zhou

  • 0
    TI__Expert 5145 points

    Hi Zhou,

    Are the boards placed in the same environment before your customer start the test?

    If this is the case, probably in the customer boards there is some source of heat that change the PCB temperature, and consequently the humidity value around the HDC sensor. The warm up time of the customer board is probably 120 seconds.

    Could you please ask to your customer to repeat the same test but monitoring also the temperature, and provide to us the data?
    Thanks in advance.
    Best regards,
    Carmine

  • 0 in reply to Carmine Iascone
    TI__Expert 4250 points

    Hi Carmine,

    Customer just left the board(power-off) in ambient temperature and ambient humidity for like 3-4 hours, then they powered on the board and found slow settling problem. Customer cannot not log-on every samples, but initial reading and final readings. Is this OK?

    I got something similar with HDC1080 EVM, if the EVM is power-off like 3-4 hours. I got following capture, the final humidity is 63.6%. The EVM took around 2000 sampling period to reach 63.6%. The reading gradually increases from 61.7% to 63.5%. If the sampling period is 30ms, the total settling time is 60s. Have you ever seen similar thing on HDC1080 EVM?

    Thanks a lot.

    Zhou