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Message ID: 2362     Entry time: Thu Jul 4 16:46:01 2019
Author: ScottA 
Type: DailyProgress 
Category: RFAM 
Subject: Reflow Soldering 

I have soldered one full EOM driver with the tunable inductor mentioned before, as well as another driver without connectors or the inductor. Here I will explain the process of reflow soldering in a few short steps.

Make sure that all the components can withstand the melting point temperature of the solder paste.

  1. The first consideration when reflow soldering is the amount of solder paste you should use. The solder paste should cover the pad and be uniform in height, like on C8 in the first photo, you do not need a heaping amount.
  2. After placing the solder paste, put the desired component on top where it wants to sit and push down on the components to be flush with the board. The second photo is what the board will look like when all components are placed in their position. U1 in the bottom center of this photo is an example of too much solder paste.
  3. After all your components are placed in the correct spot with solder paste underneath, put the whole board on a hot plate (cover the hot plate with aluminum foil or a sheet of metal) and slowly turn up the heat to the max over the course of about a minute (try to follow temperature curve recommended for solder paste). Make sure to put the fan behind to catch the solder smoke. This is shown in picture 3.
  4. Wait for a noticeable transformation of the solder paste into a more metallic silver color, then leave the board on for at least another minute to let the flux fully evaporate and for the solder to solidify. (Video:https://youtu.be/5cxSVJMq4jg)
  5. After, use flux remover and applicators to clean up the yellow tinge around each component. The flux remover will evaporate very quickly so be ready and use multiple times. The fourth picture shows the can and applicator.
  6. Check all the connections and look out for any shorts that might have happened.
  7. You have now reflow soldered!

The last photo shows both EOM driver circuits I used reflow soldering to make.

P.S. Questions? Ask Anchal.

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