MC33078: About MSL of MC33078.

Hi Kazuya-san,

Q. MC33078 MSL is class1. So the device floor life is unlimited under less than 30 degree C and less than 85% humidity.

    But if the device is storaged under conditions which in more than 30 degree C or more than 85% humidity,

    can the device be used with baking way base on The Reference Conditions for Drying Mounted or Unmounted SMD Packages table in IPC/JEDEC J-STD-033C?

If you are concerned about the IC's storage or uncontrolled storage conditions, it is good practice to go through the bake steps as recommended by IPC/JEDEC-J-33C - Industry Standard Handling and Storage Guideline for Moisture Sensitive Devices (MSD) in Surface Mount. 

Enclosed is TI's application report AN-2029 is TI's recommendation in handling and process surface mount IC packages.  

https://www.ti.com/lit/an/snoa550h/snoa550h.pdf?ts=1598118338065&ref_url=https%253A%252F%252Fwww.google.com%252F

If  you have further questions, please let us know.

Best,

Raymond

Hi Kazuya-san,

 Q:  1. Is it difficult to answer from TI side whether the device straged in over 30 degree C or over 85% humidity can be used or not?

The following image is what happened when C's molding or encapsulated compounds contain excessive moisture within the IC for soldering or desoldering. All molding materials will absorb moisture in some degree. We are not talking about surface moisture absorption here. We are talking about the moisture absorption within the molding package itself. The video below at approx. 7:56 timestamp talks about the possible damages. 

I know that this is going to extra baking steps. This is prudent steps if the parts have been left on the shelf for a while or exposed to possible near dew point ambient environment. If there are issues found after wave or reflow soldering process, there will be more work in resolving the matter. 

https://training.ti.com/ti-precision-labs-op-amps-board-level-troubleshooting?context=1139747-1139745-14685-1138808-1137167

 Q2. I couldn't find any information in IPC/JEDEC-J-33C and AN-2029 for the customer answer.  Is it needed to evaluate by the customer because TI doesn't have any information about that?

The IC parts should be stored in a desiccator jar/cabinet or sealed in a vacuum bag. Since I do not know how part is stored, I am unable to answer  the question. It does not hurt the performance of ICs when baked steps are applied in an oven per IPC/JDEC-J-33C guide lines. This is common procedures when dealing with components that may expose to unspecified humidity or higher dew point environment for a period of time. 

Best,

Raymond