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RTOS/TMP112: TMP112----Power consumption problem TMP112 shut down mode

Dany W
Intellectual 310 points
Part Number: TMP112
Other Parts Discussed in Thread: CC1310

Tool/software: TI-RTOS

Hi

    I have a question.

   I used cc1310 to drive TMP112 acquisition temperature. When TMP112 in shut down  mode, the current consumption is 2.2 uA,  Data manual is 1 uA.

 Why is this?

  • 0
    TI__Mastermind 42145 points
    How are you measuring current consumption? Is there activity on the I2C bus during your measurement?

    Ren
  • 0 in reply to Ren Schackmann
    Intellectual 310 points

    Hi Ren

    I weld an independent tmp112 module (onlyTMP112、 upper pull resistors and capacitors), The power and pin (SCL and SDA) are connected  to the 3.3 V and IO ports on the MCU board. The multimeter current is connected to the positive electrode of tmp112.  The measured current value was 2.2 uA

    The connection diagram is shown below:

  • 0 in reply to Ren Schackmann
    Intellectual 310 points

    Ren Schackmann said:
    How are you measuring current consumption? Is there activity on the I2C bus during your measurement?

    Ren

    The connection diagram is shown below:

  • 0 in reply to Dany W
    TI__Mastermind 42145 points
    1uA is very small and not trivial to measure. Here are some things to consider:
    Current through the pull-up resistors is not included in the Iq spec.
    A 3MOhm leakage path from your 3.3V supply to ground will contribute 1uA of error. Your solder work must be clean to prevent these leakages.
    Activity on the I2C bus, even if it is unrelated to TMP112, will cause TMP112's current consumption to increase. The amount consumed increases exponentially with frequency. See Figure 6.
    Hand held multimeters are not capable of measuring very low currents. We use a 6.5 digit bench multimeter to resolve the typical current of 0.5uA.

    Ren
  • 0 in reply to Ren Schackmann
    Intellectual 310 points
    Thank you for your answer
    According to your suggestion, I again under test