My Texas Instrument DC DC Converter - p/n TPS82130SILT - is a leadless device and has gold pads. I am looking for process tips to pre solder the gold pads prior to installation and am limited to primarily a solder pot. I have had mixed results using various fluxes and pre heating the device/s but none with consistency or to target conditions. I would appreciate any process recommendations that can aid in this effort.
Hello Edfrarnham,
Welcome to our community and that you for using the Digikey Tech Forum!
I will check with my team and get an answer back to you.
Thank you for your patience.
I don’t believe pre-tinning such parts is either necessary or recommended, and it is more likely to cause harm than help with the board attachment process.
See the following documents for relevant information found here:
Hi David and thanks for the feedback.
I agree that this device with its heat sensitivity rating and thin board construction should be left alone. It was the slight discoloration on a couple devices of the gold pads that convinced me to test the pads and attempt to wet them to ensure reliable solder ability.
I will save your links and refer to them as I proceed forward as appropriate.
I appreciate your support.
Hi @edfarnham ,
Welcome to TechForum.
The spots on the solder joints indicate too much flux, incorrect flux, incorrect solder, solder impurities and/or incorrect solder temperature.
Agreeing with David_1528, no need to pre-tin the pads. If you are having solderability issues, review of your soldering process will have to be completed. If you are soldering the parts using a reflow oven, you may need to check the oven profile, and also check if the type of solder being used is correct, along with checking if the stencil thickness is correct.
If you are soldering the parts using wave soldering (or solder pot) there are some tips below:
- Use leaded solder if possible, as leaded solder is easier to work with (if your design doesn’t have to be rohs compliant)
- Make sure the solder wave pot or solder pot is set to the proper temperature according to manufacturer recommended solder temperature specifications
- For solder pot, Stir the pot every few minutes to keep solder consistent and scrape the top layer of solder in the pot before dipping, as the layer that naturally forms on top doesn’t make good solders
- Make sure to use a flux formulated for leaded solder if you are using leaded solder, or a flux formulated for non-leaded solder if you are required to use non-leaded solder. Some solders recommend a certain flux type per their datasheet. The solder and flux must always be compatible.
- Don’t over-flux the pads, the spots on the solder joints is a result of too much flux, or poor solder quality/temp
- Don’t mix solders
- Upgrading to a higher quality solder & flux may be a solution. Kester ULTRAPURE® would be a great series to choose, if at the very least to troubleshoot if the solder is to blame. Remember to choose the correct flux per product datasheet and use recommended solder temperature:
