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TMP101 ALERT Output

hisakichi kobayashi
Intellectual 950 points
Other Parts Discussed in Thread: TMP101

Hi all,

It's using TMP101 by my user. The following phenomena are seen in the TMP101.

Power supply (3.3V)---> power supply (about 70 msec)---> power supply (3.3V)--=> After about 20 msec(s)
From an ALERT output   For [ Low Level ] about 40 ms is outputted.

Thus, is ALERT:Low outputted for a power supply start-up and tens of ms?

Best Regards,

Hisakichi Kobayashi.

 

  • 0
    Intellectual 950 points

    Hi all,

    Mistake!

    Power supply ON (3.3V)---> power supply OFF (about 70 msec)---> power supply ON (3.3V)--=> After about 20 msec(s)
    From an ALERT output   For [ Low Level ] about 40 ms is outputted

  • 0 in reply to hisakichi kobayashi
    TI__Expert 7945 points

    Hello Hisakichi-san,

    Please check on the following possible causes of the issue here:

    1. Do you have a bypass capacitor at the power suppy? The reason I ask is 70msec may not be enough time and TMP101 internally has an ultra-low power reset circuitry that will not completely reset unless the voltage level goes down all the way to 0V. There is a good chance that this is occurring or the bypass capacitor (if it exists) is not completely discharged before customer powers it back on after 70ms. Can yoiu check for Voltage levels using a scope. Also how long is the device ON for Initially?

    2. Is the customer changing any default settings on the ALERT pin by writing to the Configuration register?

    3. Does the ALERT pin has an external pull-up?

    It would help debug if you provide more information like scopeshots, achematic etc

    Regards,

    Abhi

  • 0 in reply to Abhishek Muppiri
    Intellectual 950 points

    Hi Abhishek,

    Qestion to answer.

    1. 0.1uF Ceramic Condencer x1 Piece   (between 3.3V to GND)
    2. Anyway, since it is a talk immediately after power activation, even if it is a register, it has not set up.
    3. The pull-up is to 3.3V by several kohm resistance.

    Scopeshot is not open.

    Regards,, Hisakichi Kobayashi.

  • 0 in reply to hisakichi kobayashi
    TI__Expert 7945 points

    Hello Hisakichi-san,

    Thanks for the answers. Can you advise the customer to turn off TMP101 for a longer duration say for about 1 second and see it if this issue occurs again.

    To be able to advise you better I will need more information from you. Scope shots of this phenomenon will help us reproduce the issue case scenario here..

    Regards,

    Abhi

  • 0 in reply to Abhishek Muppiri
    Intellectual 950 points

    Hi Abhishek,

    Scopeshot is open,

    6886.TMP101_波形観測結果_140318.pdf

    Do you think scopeshot?

    Regards,

    Hisakichi Kobayashi

     

  • 0 in reply to hisakichi kobayashi
    Genius 4705 points

    Hi, Abhishek-san,

    I will explain a little bit about the scorpshot.
    This behavior occurs at a frequency of about 1/1000 cycle.
    Waveform of the two types has been observed when the ALART becomes Low.
    The width of the period of the Low ALART is 75ms and 40ms.
     
    I am guessing this phenomenon,  as being dependent on the rise time of the power supply.
     
    Regards,
    Toshi