ADT7302 Data Rate and Thermal Time Constant

Hi All,

My customer would like to know the maximum available data rate with ADT7302. The data sheet says conversion time is 1.2ms. And the devise clock is reset after every read or write operation for register and this cause the device to start a temperature conversion.

Does this mean the maximum data rate through interface is 1/ (1.2ms + register read time), around 80sps. Is this correct?

My customer also want to find device which has short thermal time constant. The thermal time constant of ADT7302 is 2 sec. Do you have any other recommendation which has minimum thermal time constant?

Best Regards,

Ricky

  • 0
    •  Analog Employees 
    on May 5, 2015 9:20 AM

    Hi Ricky,

    Your assumption here seems ok. A conversion takes typically 1.2ms, and the internal clock is reset after a write/read operation, so this time is what is conditioning the sample rate as you pointed. Note that a conversion has to be completed before a read occurs, otherwise the result does not get loaded into the temperature value register. Is this sample rate actually critical? Would the 80 SPS you calculated be suitable here? By the way, what frequency is your interface clock running at?

    The 2 sec thermal time constant data you mentioned is the time the part would take to reach the 63.2% of the final value, but when a thermal shock from 0C to 100C is applied. Would that be your case in your end application? Note also thi 2 sec is a typical value.

    Regards,

    Lluis.

  • Hi Lluis-san,

    Thank you for your response.

    I will talk to my customer based on your advice.

    Best Regards,

    Ricky