• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 30 subscribers
  • Views 786 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

TMP275: TMP275 Output has random 1.5C jumps

Troy Daiber
Prodigy 20 points
Part Number: TMP275

I am troubleshooting someone else's design.  The output has steps of +1.5C or -1.5C.  Additionally, temperature is reported at 10-15C below expectation.  When the 1.5C steps are added into the data, as if to "correct" the data, I see that the reported rate of increase is the same, before and after the jumps.

Wiring:  Address 0x4F; operating at 3.3V;   SDA & SCL are connected to micro-controller via two 33R resistors, no pull ups to 3.3V;  Alert is not connect nor pulled up.

  • 0
    Prodigy 20 points
    Correction: The SDA & SCL are in fact pulled up on a peripheral board.
  • 0 in reply to Troy Daiber
    TI__Mastermind 37370 points
    Hi Troy,

    Thank you so much for your generosity. Let me try to understand your statement. You are using TMP275 temperature sensor, and connected the SCL and SDA in series with 33Ω with pull-up resistor connect on the other side of the peripheral board. When you read the TMP275 at room temperature you are seeing an offset of 10°C to 15°C with ±1.5°C noise coupling in.

    1. Since you are using a secondary peripheral board, do you know how many devices attached on the I2C bus?
    2. What is the address pins (A0, A1, A2) set to?
    3. Could you please provide me the schematic?
    4. When you read an offset temperature of the TMP275, can you capture the waveform and send to me?

    Aaron
  • 0 in reply to Aaron Heng
    TI__Mastermind 37370 points
    Hi Troy,

    I did not see your response. Assuming you resolved the issue. I will close this thread, let me know if you need further assitance. You can reopen the case again anytime.

    Aaron