EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: GG on January 04, 2025, 09:39:34 pm
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Dear EEVblog,
I'm fairly experienced in SMD soldering but I'm not sure if and how I could solder the component in the attached photo using my TS100 iron.
I know a hot air station would be the easiest but for a one-off project I would prefer to use what I already have.
And help and advice would be greatly appreciated.
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If you make extended pads that protrude well beyond the outline of the module, you miiiight be able to do it. Or by using square plated through-hole pads and soldering them from the other side. But this package is very clearly designed for reflow soldering in an oven.
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Thank you for your prompt reply Tooki.
I designed the PCB to have protruding pads for this component, like you said.
I saw a video about putting sand in a pan and putting the PCB with solder paste+flux on top of this sand with the component on top, is that something that actually works?
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For hand soldering with an iron - extended pads, as already suggested, but also, pre-tin the pads on the component, and pretin the pads on the PCB. Not much at all, but just enough to cover the pads, you don't want some pads higher than others so it rocks over the uneven pads. Solder paste might be better here because you can more easily control the ammount on each pad. In either case, if you add too much, use solder wick to get rid of the excess.
Then just heating the PCB pad with the component placed should allow enough heat to transfer to the component pads to melt the (little) solder on them, one by one. Pre-tinning helps because you don't have to get the solder hot enough to heat up the component pads to tin it, its already done before hand.
If not using an iron, hot air on the underside of the board. Assuming that none of the pads are connected to a large ground/power plane, it should be enough to get every pads hot enough.
Thankfully these pads are so close to the edge you can easily see if each connection is soldered, and if some aren't you can just touch them up with hot air from below with a narrower nozzle to target a specific pad.
Please, don't use the sand/pan method. Yes, it can evenly distribute heat across the PCB, but what are you heating it with? If it isn't temperature controlled, don't do it. People get stoves/hobs with pans and sand to work by luck, and by not caring about destroying components and/or PCBs. You don't have to be within single digit degree, but +/-40 can make a hell of a difference, and cookers ovens aren't that accurate, and their hobs certainly aren't.
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I'd go with this component first and use a heat plate with solder paste on the pads. Maybe use some lower melt type to not cook the device.
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You can buy a hot air soldering station quite cheaply on eBay, around 30 GBP, $40, or so.
That board is badly designed, you will struggle to solder those pads, even with pre-tinning, flux and hot air will probably work, but it’s hard to be certain you have soldered each pad.
A similar GPS module, a Ublox M8T, that I have soldered, has the board pads at the edge of the board and are plated up the sides of the board… easy to solder by hand.
SJ
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Thanks very much for all your suggestions, much appreciated.
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You can already buy it with the connections broken out into through-hole connections; Adafruit sells it. It will cost more, but that will guarantee you success in connecting it if you don't have the tools. It will save a lot of time, too.
Personally, I would not use this module regardless, because the datasheet isn't very helpful, and there's no recommended layout (maybe I missed it). For the best performance, there's supposed to be a ground plane.
Maybe the best performance isn't needed for a hobby project, but if I'm going through the effort of making a custom PCB and soldering that more difficult package, then for that effort I'd want to try to lay it out as the manufacturer recommends specifically for the antenna aspect (because they spend tens or hundreds of $k determining the best layout for that part, so why not make use of that for free if possible).
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I know a hot air station would be the easiest but for a one-off project I would prefer to use what I already have.
I agree with this approach, but from experience, sometimes a project that may have cost you money for someone else to build/manufacture justifies spending money on a tool that will come in handy for future projects.
The one I own is: Hot Air Pencil 852Dplus
Don't remember the cost, but believe it was around $75. It came with everything I needed, however, I needed to purchase more nozzles which I found on eBay for $20 that was a 12pk full of various sizes.
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Flux and tin the component underside corner pads slightly raised with solder bumps. The other pads slightly less. You can inspect the component side-on to ensure it's fairly uniform.
Flux and tin the pcb pads and use wick to clean them flat. Clean flux from both pcb and component and apply a small amount of fresh flux to both.
Position the component and hold it in place from the opposing corner first soldered.
Clean and tin your soldering tip well (mostly important step) remove excess solder. Load a small amount of solder to the tip and touch to the corner pad to be soldered.
Allow enough time and heat for the solder to wick up and bridge to the component, if you apply too much solder for a clean looking fillet then remove and prep again adjusting.
Allow the joint to cool before moving your positioning hand. Solder the other corners and then other joints. Each time cleaning the tip and applying the exact amount of solder to make a uniform fillet.
The end result approximates hot air or oven reflow.
Edit:
If you are overly generous the trick to removing a slight amount of solder is to clean the tip and use a little flux and retouch the joint. You can also flux copper wire as improvised mini wick.