Part Number: LM8272
Tool/software:
I am reaching out to request Coefficient of Thermal Expansion (CTE) data for the component we have sourced from your company. Could you please provide us with the CTE values ? We would appreciate it if you could provide the CTE values in ppm/°C or ppm/°F, as well as the temperature range over which the values are applicable.
Hi Tamren,
Could you please provide us with the CTE values ?
Here is the molding compound composition for LM8272. The CTE value can only be specified in an range, since Tg of the molding compound is difficult to control due to the epoxy crosslinking process in a chemical reaction.
https://www.ti.com/materialcontent/en/report?pcid=211402&opn=LM8272MMX/NOPB
Coefficient of Thermal Expansion (CTE) is a function of molding compound's curing temperature or Tg (glass transition) based on the above epoxy composition.
Typically, Tg of the op amp molding compound is approx. 130C +/-20C.
Tg is the glass transition temperature:
When a molding compound's bulk temperature is below its Tg temperature, the material tends to be hard, rigid in glassy state and a material's CTE tends to lower, which the polymer crystalline phase is called Alpha-1.
When a molding compound's bulk temperature exceeds its Tg temperature, the material's mechanical behavior is more flexible (polymer is relaxed) and rubbery, and a material's CTE tends to be higher, which the polymer crystalline phase is called Alpha-2.
When a molding compound's bulk temperature is approaching or exceeding its Tg temperature, which it refers to the material's glass transitional temperature. It is the onset temperature between changes in Alpha-1 and Alphase-2 phase.
Here is the CTE ranges in Alpha-1 vs. Alpha-2 phase figures.
If you have additional questions, please let me know.
Best,
Raymond
