Best way to solder a TSSOP20? - Page 1
Forum section: electronics / general

author: Faringdon
author_rank: Super Contributor
timestamp: August 07, 2022, 09:29:15 pm
content: Hi,Just developed a new way to solder TSSOP20..eg UCC28070A. (0.65mm pitch)I have never seen this on youtube, or anywhere...Does not use...1....Hot air2....Hot plate3....Braid (no mopping up with braid and getting braid stuck to several pins)Just uses a (pref regulated) soldering iron with a pointed tip, approx 0.5mm, and a bit of flux on the pads to start off. And some brass wool to wipe the excess solder off repeatedly.Just uses the principle that solder is attracted to the hotter surface.First tack down the four corner pins, 1 then 11, then 20, then 10 (go diagonally)Then simply give each pin a generous soldering.Dont worry about shorted pins.Then simply turn the soldering tip to that temperature which tends to attract molten solder off the shorted regions to the tip, and literally kind of pull the solder off the shorted bits and wipe it off in brass wool, repeatedly.Try and motion the tip between the pins so it pulls the solder short out.If the solder short wont move , then tease it fom pin to pin till its at the edge pin.......when its there, its easy to pull it out by kind of pulling toward the edge with the solder tip. (at the edge, theres no adjacent pin for it to short to)For some reason its easy to pull the short "sideways" from an edge pin...and when you do that, you unshort the edge pin.Alternatively, and this is usually not needed...just use a tiny pinpoint of braid to unshort this last edge pin short.The secret is in getting the tip to that temperature which is hot enough to pull off the solder from the shorted bits...pulling it off onto the iron, where you wipe it off on brass wool.Does anyone have any enhancements for this.....eg better tip shapes for it etc?

author: jpanhalt
author_rank: Super Contributor
timestamp: August 07, 2022, 09:37:59 pm
content: Congratulations on success. Your method is not a lot different than the drag method with solder braid. But hopefully, some will find it useful. My concern with wiping with brass wool is that unless it is quite fine, you run the risk of pulling a pin off its pad.I use the drag method with solder wick. Even then, a light touch is needed.

author: Faringdon
author_rank: Super Contributor
timestamp: August 08, 2022, 08:51:00 am
content: Thanks, just in case i explained wrong, i wipe the solder tip in brass wool, not the soldered pins.......when i "dab" the solder iron to extract the short, it is ensured the iron is hot enough so that it doesnt pull the pin and "break" it.....

author: retiredfeline
author_rank: Frequent Contributor
timestamp: August 08, 2022, 09:19:47 am
content: Same as you I tack down the corners, then I apply solder pastesparinglyto the legs, but not the knees. I then swipe a chisel tip in a diagonal outward motion to melt the paste.

author: zzattack
author_rank: Regular Contributor
timestamp: August 08, 2022, 09:32:42 am
content: Only solder 2 corners instead of 4. There's always too much solder on a single pin if you do it manually, which leads to higher chance of bridging there. Then begin soldering from the other side (so tack pin 1, start soldering at pin 10 in your example).With good flux, consistent travel speed and very light pressure from the iron, the solder should follow the tip nicely and it's very possible to not have any bridges in the first place. If bridges do form, using a hoof-/reservoir-style tip makes it very easy to solve them because the reservoir has nearly a suctioning kind of pull.

author: Faringdon
author_rank: Super Contributor
timestamp: August 08, 2022, 10:08:01 am
content: QuoteThanks, you mean like a two pronged tip, and the solder gets kind of drawn into the "web" in between the prongs?

author: Kean
author_rank: Unknown
timestamp: August 08, 2022, 01:30:08 pm
content: Quote from: Faringdon on August 08, 2022, 10:08:01 amThose can work, but normally a concave/hollow style tip is recommended for drag soldering.See this for some recommended tips and methods for drag soldering from Hakkohttps://www.hakko.com.au/maintenance/search-by-tip-shape/tip-selection/work-drag/

author: rooppoorali
author_rank: Regular Contributor
timestamp: August 16, 2022, 10:00:18 am
content: Would like to see a video of your method. Thanks.

author: TomS_
author_rank: Frequent Contributor
timestamp: August 16, 2022, 09:03:59 pm
content: It's not a particularly new technique, people have been doing it for ages.Ben Heck has one such example demonstrating it:https://youtu.be/oGB7Yrbeo_Y

author: jpanhalt
author_rank: Super Contributor
timestamp: August 16, 2022, 09:23:44 pm
content: Considering the combination of worries about manufacturers' and distributors' using appropriate ESD precautions and this, I am beginning to suspect user/poster error. Not anything else.

author: Faringdon
author_rank: Super Contributor
timestamp: August 17, 2022, 01:25:06 pm
content: QuoteThanks...its pretty much TomS's kindly supplied video at 11 mins. (Reply #8 above)Must admit i have to spend a lot more time picking out the shorts than he does.

author: tooki
author_rank: Super Contributor
timestamp: August 17, 2022, 07:45:53 pm
content: Try this, in no particular order:1. Reduce your iron temperature. Higher temps = faster oxidation = more shorts and dags2. Re-tin your tip with fresh solder more frequently3. Add flux