General > General Technical Chat

Come in through-hole components your time is up!

<< < (3/13) > >>

VK3DRB:
PTH is still very relevant in some situations.

EXAMPLES:
  TO-220 devices when needed to be connected to a vertically mounted heatsink.
  SMA connectors on PCBs. Why? Mechanical robustness.
  DC power input connectors or photo jack connectors. Why? Mechanical robustness.
  Female header connectors. Why? Cost.
  Optocouplers. Why? Isolation, although you can now get many in SMD with the same isolation characteristics.
  PCB mounted speakers. Why? Cost and availability.
  High power resistors.

Other than those and a few other examples, SMD is the way to go. These days, there is little reason or excuse not to use SMD in general. My eyesight is not crash hot, and yet I can solder 0402 resistors without too much fuss. I have even hand soldered 0201's - not much fun, but doable.

For SMD, older folks might need some visual aids. You will need a decent soldering iron, decent solder, decent flux and decent tweezers. A hot air de-soldering tool helps too.

PTH ICs are generally very old school. It's like wearing flares and body shirts. You'd look like a dag. Time to get with the times.

hans:
TH ICs are being phased out. NXP dropped all their DIP parts for their logic ICs and other legacy ICs (like some old microcontrollers).

However, I see this more of a materialization of a decision taken 10-20 years ago. Look up any modern analog signal or digital logic chip. Almost none of these are available in DIP. They are all at least SOIC, often SSOP packages. I wouldn't be surprised if more silicon vendors like TI will follow in the upcoming 5-10 years.


Dave did a great soldering tutorial on SMT. There are not that many tools required to do the job, although some people may find a microscope a necessity if they have unfavorable eyesight. For me I only use a 4x loop for inspection.
I wouldn't even get too dragged along into using flux for every solder joint. The stuff smells, sticks, makes a giant mess, and with good fresh solder there is also flux inside it. Only for QFP or QFN chips I will use flux to make sure the soldering job will succeed.

rs20:
VK3DRB, you can add other large passives to that list (capacitor, inductors) too. Easier to solder, soldering process doesn't stress the part as much, and more mechanically robust.

ZeTeX:
My lab is stocked with TH parts, how am I supposed to transfer it all to SMT?
I'm very slowly trying to buy only SMT and use only SMT but I have a lot of TH capacitors, resistors, op amps, diodes, bjt, fets, what not, and I can't afford to just stop use them and order a LOT of SMT parts.

For a beginner who just started I can advice to use SMT when can, and try to order mostly SMD.

brabus:
During one of my latest product designs, I could not afford to mount an SMD 3.5mm jack header, due to the fact that all the stress is taken by the solder joints and I did not want random jacks to detach themselves from the boards on the field. I found a very good PTH part, which allowed me even some space saving on the PCB, thanks to the straight vertical pins instead of SMD large pads.

The choice between SMD and PTH was in some other cases more fine, e.g.: high voltage paths, mechanically/thermically stressed PCBs, solderability (does this word even exist in English?), producibility.

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod