• State
  • Locked Locked
  • Replies 4 replies
  • Subscribers 48 subscribers
  • Views 288 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DDC264 maximum integration time limit / beyond datasheet!?

Stefan Langer
Prodigy 125 points
Other Parts Discussed in Thread: DDC264

I'm happily using two daisy-chained DDC264 but one question appeared:

Despite the datasheet states maximum integration time to be 1s for DDC264C and nothing for DDC264CK

Q: what happens at longer integration times?

Q: Is there a way of increasing integration times beyond 1s?

Q: Is performance degraded? If so, why?

Q: is it an error that the datasheet dos not give max. int. time for CK-part?

  • 0
    TI__Mastermind 18275 points
    Stefan,

    We have received your post and hope to have a response back to you soon.
  • 0
    TI__Mastermind 49176 points
    Hello Stefan,

    We have received your inquiry regarding the performance of the DDC264 at certain test conditions.
    I have assigned your post to the device applications expert.
    He should get back to you as soon as possible.
  • 0
    TI__Guru 61310 points
    Stefan,

    Looking at the DDC264 datasheet page 3, I see 1,000,000uS or 1 second listed as the maximum integration time for both C and CK versions. Is it blank somewhere else?

    Longer Integration times can get tricky because you start to really accumulate a lot of the device's Ibias current and integrated noise. Accuracy will degrade but you can certainly try it depending on your accuracy needs. Looking at the datasheet Noise vs. TINT plot on page 7, you can get an idea of how this noise adds up over time. In theory the device will integrate until you tell it to stop, we just don't have data for longer TINT than listed in the datasheet.

    Regards,

    -Adam
  • 0 in reply to Adam Sidelsky
    Prodigy 125 points

    Thank you Adam for answering that quick.

    The "blank" I meant was on page 15, table 3....

    Sadly figure 7 lacks ranges 0-2 and also 1s (I assume the line would end at ~12 for 1000ms?) and figure 8 lacks range 0 (assume it is parallel to other curves starting at 34ppm).

    Can I assume that noise increases with int. time by roughly the same amount shown in figure 7 for the other ranges as well?

    e.g. range 0 starting with ~34ppm at 166µs and increases roughly by 1/3rd at 100ms?


    I will implement longer int.times (up to 10s) and report my findings.