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LM2907-N: SMT Soldering

Josef Alt
Intellectual 1705 points
Part Number: LM2907-N

Hi,

my customer wants to use LM2907MX-8/NOPB in an SMT production line. The datasheet specifies an infrared soldering temperature 220 degC. 

however for an lead free SMT soldering process the following parameters are required:

238degC < Tmax < 248degC for all soldering pads

55 sec < Time above 217degC < 65 sec.

Can you please specify at which temperature the customer can solder the part. The target is to be significantly above 217degC for 60 seconds total. 

Thanks

Josef 

  • 0
    TI__Guru* 93105 points

    Hello Josef,

    It appears that there is little information about infrared soldering temperatures for ICs on TI.com. Most of TI's soldering information is focused on non-IR wave soldering. The LM2907-N is about the only datasheet I could find that listed the infrared soldering conditions. I found one TI Applications Report (snoa292) that makes a brief mention in Section 2:

    "For maximum convection or convection/IR reflow conditions see JEDEC J-STD-020."

    https://www.ti.com/lit/an/snoa292j/snoa292j.pdf

    Here's a link to the JEDEC standard I found online:

    https://docs.broadcom.com/doc/J-STD-020D-01.pdf


    The JEDEC document states, "3.2.2 - Infrared Infrared (IR)/convection solder reflow equipment capable of maintaining the reflow profiles required by this standard. It is required that this equipment use IR to heat only the air and not directly impinge upon the SMD Packages/ devices under test."

    Where the key phrase is "Infrared Infrared (IR)/convection solder reflow equipment capable of maintaining the reflow profiles required by this standard." Thus, it would appear that the IR reflow system would be held to the same maximums of the other types of reflow systems.

    The LM2907-N datasheet was developed by National Semiconductor decades ago and TI has manufactured it since the National acquisition about a decade ago. Since TI specifies the JEDEC J-STD-020 standard it would dictate the IR soldering conditions that modern LM2907-N product would be able to safely withstand.

    Regards, Thomas

    Precision Amplifiers Applications Engineering