4
\$\begingroup\$

I want to try reflow soldering for several projects (small scale). For some of the components (e.g., resistors and ceramic capacitors), the datasheet does give specific information about maximum temperature, and some of them even have a (very detailed) drawing of the recommended reflow temperature profile!

However, not all of them. For example, I have the AD8421 instrumentation amplifier which does not say anything; the Absolute Maximum Ratings section includes the Maximum junction temperature, reported at 150 °C.

I'm not sure what this "maximum junction temperature" means or represents; but it is more than 30 °C lower than the melting point of tin/lead solder, so hopefully it says nothing about the maximum soldering temperature.

As the subject says: I'm just wondering whether I could blindly trust that all (or at least the vast majority of "normal" SOIC chips) will resist the few seconds at 235 °C.

Any comments / advice will be appreciated.

\$\endgroup\$
5
  • \$\begingroup\$ googling "analog devices reflow profile" gave me analog.com/media/en/quality/RoHS_Compliance_General_Info.pdf which says "RoHS compliant indicates the packages can withstand a peak reflow temperature of 255 +5/ - 0 deg C" \$\endgroup\$
    – pjc50
    Commented Nov 10, 2015 at 19:41
  • \$\begingroup\$ For any SMD component I usually use a temperature between 300 and 320ºC. The temperature is important, but more important is the time exposure at a given temperature. Anyway, if you have the information in the component datasheet is strongly recommended follow it. \$\endgroup\$
    – Gabriel Rezende Germanovix
    Commented Nov 10, 2015 at 19:50
  • \$\begingroup\$ Any RoHS compliant component SHOULD be rated to 260C, although there are a few that are only 230C for some reason. Also some larger manufactures like AD, have a global doc for re-flows, not device specific instructions. \$\endgroup\$
    – MadHatter
    Commented Nov 10, 2015 at 19:55
  • \$\begingroup\$ Answering to Respawned Fluff: You would have to ask the designers of stackexchange / stackoverflow / etc. I signed the same way I've always signed every electronic communication: my nick, <ENTER>, dash dash ... then, the message composer thinks that that should be displayed at four times the size and in boldface .... whatever they say.... :-O \$\endgroup\$
    – Cal-linux
    Commented Nov 10, 2015 at 20:35
  • \$\begingroup\$ In general, a part that is "lead-free" must be able to survive a profile for SAC305, i.e. tmax 260C. There are exceptions, check with the manufacturer if you really care. If you can't find info on their site send them an e-mail. \$\endgroup\$
    – Oleg Mazurov
    Commented Nov 10, 2015 at 21:38

1 Answer 1

Reset to default
1
\$\begingroup\$

Any reputable device in their datasheet will have (in case you are not familiar) a "Solder profile" that indicates not only the peak temperature, but also the ramp-up temperature rate, dwell temperature rate and cool-down temperature rate. Make sure your manufacturer adheres to this solder profile and you should be good. Violations of this soldering profile, which I have seen personally for LEDs, actually desoldered the internal binding wires from the LED die. So yes, the LED is on the board, but it is not guaranteed to work (because we were not following the solder profile).

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.