ADT7410 temperature issues

Dear Team,

I am facing issues in temperature values of this sensor. I am getting zero degree Celsius after power ON and configuration  to continuous conversion mode (default). After sometime the IC is displaying correct value. The same IC is creating the issue at high temperature (+71 degree C) and also at low temperature (-40 degree C). There is randomness in the IC behavior while displaying the correct value. I have used totally 4 ICs on board-1 and 4 ICs on board-2 but all the 8 ICs (ADT7410) are showing similar behavior. I am using default 13-bit data conversion format.

I have read the default of the following registers after power-ON and they seemed as per datasheet : 

I re-read the values after configuration to 1 SPS mode also and got the expected register values.

I read the values of the configuration register as per below screenshot : 

Reset issue:

On resetting the IC as per : 

I am writing 0x2F in the address 0x2F but the IC is not completely getting reset. I read the configuration register 0x03 (screenshot attached above) but I am reading 0x80 instead of 0x00 (default value). 0x80 means that its going to 16-bit data conversion format although I am using 13-bit data conversion format which is the default settings.

Note:

  1. Once the sensors start displaying correct values at ambient temperature then they show correct values throughout till the unit is ON.
  2. Once the sensors shows zero degree C/ any other wrong values at high/low temperature then they continue to show wrong value till the temperature is brought close to ambient.
  3. Pull-up resistors of 10 K is already used in SDA and SCL lines.  
  4. 0.1 uF is used for VCC of ADT7410 IC.
  5. We are able to identify all the 8 sensors (4 sensors on Board-1 and 4 sensors on Board-2) by its address individually and also read them.
  6. The clock frequency is 97 KHz for SCL.

Please help us resolve the issue as soon as possible. The issue has been unresolved for more than 2 months and we are not getting any solution. Kindly consider this as high priority.

  • 0
    •  Analog Employees 
    on Nov 20, 2020 7:07 AM 4 days ago

    Hi, 

    Apologies for missing this. Has this issue been resolved? We have received this query in email as well and have asked for scope shots of the clock and data signals when all is working at ambient and when the issue comes up. We didn't get those so if you have them please send them on so we can have a look.

    Regards,

    Karen