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TMP123: First effective data output timing after power supply

cafain
Mastermind 6755 points
Part Number: TMP123

Hi,

First effective data output timing after power supply

1)After VDD supply, is the first temperature conversion data valid data?
　or
  Will conversion data from the second time become effective after VDD supply?

2)After VDD supply, can CS be kept "H" level for 320ms, then CS is set to "L" and valid conversion data can be read by reading converted data?
* We are referring to Data READ Timing in the data sheet in Figure 3.

best regards

  • 0
    TI__Mastermind 43705 points
    Hi cafain,

    1. The first conversion should be valid data. Are you seeing an issue? A power glitch or unusual voltage ramp could potentially corrupt the first conversion.

    2. Yes, I think your understanding is correct.

    Thanks,
    Ren
  • 0 in reply to Ren Schackmann
    Mastermind 6755 points

    Hi, Ren-san

    I appreciate your quick support.

    After supplying V+ power to TMP123, temperature data was read from TMP123 under the following conditions.
    There is a big difference in temperature data even though there is no change in room temperature.

    ・After turning on the power, wait about 500ms and read TMP123 by SPI communication, you can read about 20℃.
    ・After turning on the power, wait about 800ms and read TMP123 by SPI communication, you can read 28℃ (room temperature).

    Some devices showed 226.375℃.
    In the experiment, it was confirmed that the time after power-on affected the data.

    What causes the temperature data to differ greatly?
    I look forward to your advice.

    best regards

  • 0 in reply to cafain
    TI__Mastermind 43705 points
    Hi cafain-san,

    Can you show me oscilloscope pictures of the communication? I'm especially interested in seeing the 226° transaction.

    Thanks,
    Ren