Last updated on January 25, 2009
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Since I’m in a posty mood tonight, have a photo of the smallest thing I’ve soldered to date. It’s nowhere near as small as what some folks I know have done, but I’m pretty happy with it. This part, U1D, is a Texas Instruments TPS2115APW, which handles automatically switching the AMB γ1 between wall and USB power, giving priority to USB whenever it is plugged in.
The package of this part is TSSOP-8, which has 0.65mm between centers of the pins, with the pins being 0.19mm – 0.30mm wide. I soldered it with a Weller WES51 with an ETO tip. Kester 24-6337-6417 (Water Soluble 331 Solder Wire, .025″ dia., Core Size-66 Sn63Pb37) solder was used along with a 2331-zx flux pen. Chemtronics Soder-Wick Rosin SD desoldering braid, in size 3, was used for cleanup.
Soldering was done with the iron set at 700°F. The area was coated with flux, a pad was tinned, more flux was added to that pad, then the part was placed. The iron was then touched to the edge of the pad and the part settled into place. Any slight adjustment would be performed by reheating the pad and moving the part slightly with fingers or a pin, but this wasn’t needed. I then fluxed the legs of the part and very quickly tacked each leg with a bit of solder.
The solder braid was then quickly run across the legs to pull off any extra solder. When washing the PCB after assembly the rosin flux from the desoldering braid was first removed with 99% isopropyl alcohol, then while the board was still wet it was washed with hot water.
(Click here or on the image above for a full res copy of that image.)