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AD7606 - Cold start (-40 deg C) issue.

Question asked by Roger99 on Apr 17, 2013
Latest reply on May 10, 2013 by maithil

Hi,

 

I am currently using two AD7606BSTZ in one of my design. Being in engineering qualifications, I encountered problems at low temperature with one of the two devices used.

 

Observed issue:

 

·         Unable to perform cold start on one of the AD7606BSTZ on my board when ambient temperature is -40 deg C.

·         Values returned are all zeros.

 

Test Sample:

 

2 x AD7606BSTZ (U31 et U25)

Part No: AD7606BSTZ

Markings: #1130

Markings: 2173586.1

 

Test steps / Results:

 

·         Power-off unit

·         Reduce temperature from ambient to -40 deg C (rate of 1degC/min)

·         Soak for 2hrs

·         Perform cold start

·         U25 works fine

·         U31 only transmits zeros

·         Cycle power supply to the unit

·         U25 works fine

·         U31 only transmits zeros

·         Shut power off

·         Increase temperature to -30 deg C (rate of 1 deg C/min)

·         Soak for 2hrs

·         Perform cold start

·         U25 works fine

·         U31 only transmits zeros

·         Let unit warmup for 30 mins

·         Cycle power supply to the unit

·         U25 and U31 work fine

·         Power down unit

·         Increase temperature to -25 deg C (rate of 1 deg C/min)

·         Soak for 2hrs

·         Perform cold start

·         U25 and U31 work fine

 

Observations:

 

Following this test, I looked at all the solders with a microscope and all solders are ok. Wetting is perfect, no cracks in the joints, etc.

 

Questions:

 

1)     Any thoughts of suggestions on this issue ?

 

Kind regards,

 

Roger

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