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PCB Cleaning Impact on TMP006 Calculation

Other Parts Discussed in Thread: TMP006

Hi,

I have used hot gun to solder TMP006 on my new board. The hot gun is Steinel 3483. It was set to 310 degree. Solder flux was applied before soldering. I am not sure the flux type. But PCB was not cleaned as far as I knew. Afterwards, I tested TMP006 in a stable enviroment. The calculated object temperature changed from 9 degree to 16 degree even if target object temperature was stable. The range seemed larger than what I expected. So I suspected that there must be something wrong with solder or something else.

Now I look into TMP006 SBOU108. It states PCB cleaning is mandatory in section 5.4. So I guess the problem was caused by flux or residue. Is my guess right? How much does flux or residue impact on temperature accuracy?

BRs,

Luo

  • Luo,

    Solder flux residue from the assembly process can effect the measurement accuracy of the TMP006 in multiple ways: it can create a thermally conductive pathway to the bottom of the IC causing errors, produce leakages on the digital lines, or if any residue exists on the surface of the chip it can interfere with the amount of IR received by the sensor. It is not possible to determine exactly which mechanism and to what degree flux will affected the measurement in all applications because every pcb assembly is different. However, our own in-house testing indicated that thorough PCB cleaning is an absolute necessity to ensure reliable functioning of the TMP006, which is why it is included in SBOU108.