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TEMP SENSOR* TMP421

eli
Guru 13485 points
Other Parts Discussed in Thread: TMP421

Regarding TMP421,In order to measur by REMOTE SENSING function,by conect an electrode to measure fingure temp,by contact.

Were acctually I should conectted the electrode?Should it connected to the base of the transistor?

  • 0
    TI__Mastermind 25915 points
    A Message from the TI E2E™ Community
    Texas Instruments

    Chris Featherstone replied to Re: TMP421 Question in Temperature Sensors Forum.

    Alex,

    On page 15 of the TMP421 datasheet you will find the following:

    The remote channel uses sequential current excitation to extract a differential VBE voltage measurement to determine the temperature of the remote transistor.

    VBE1-VBE2 = (nkT/q) * ln(I2/I1)

    This means that the device will source current to the connected transistor two times and measure two different VBE’s for temperature measurement. On page 3 of the datasheet you will find that the source currents are in micro amps ranging from 6-120uA. Also the conversion time is anywhere from 100-130ms with a typical conversion time of 115ms.

    You can connect the electrode between base and emitter in both configurations and make sure that you measure in less than 100ms. After you measure you can use the above equation to calculate the temperature.


    E2E http://www.ti.com/e2e-community

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