US8 package prototyping

I guess I might be able to mount them "dead bug" and connect up with some very fine wire to landing pad cut-outs.

Of course, You need a proper PCB layout to solder them too. As for soldering, an easy way out is to lather all the pins with solder, then clean up with solder wick. Solder stays under the pin, between pin and pad, to make the connection.

--
 Thanks, 
    - Win

I did a PCB layout for US8 adapters and had some boards made by a quickie proto house. I hate US8s. They are almost impossible to solder or probe. But some great parts only come in US8, like the 1 ns Tiny gates and flops and buffers.

I don't know of any commercial US8 adapters.

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John Larkin         Highland Technology, Inc 

lunatic fringe electronics

You can splay out the leads to a larger DIP adapter, with some difficulty.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

I jumped on a 'scope with higher max magnification, and I've found that if I take a TSSOP-8 "surfboard" using the finest iron tip I have, I should be able to tack the middle 2 pins on each side of the US8 by hand and then tack the edge pins after gently bending them up and into place.

Yeesh. They also come in MicroPak, I dunno if that'd be any easier to work with for a hand proto

Yep trying that, it looks nicer once its cleaned up with some alcohol and seems to work OK:

Tack middle pins on each side, then once they're down use tiniest jeweler's screwdriver inserted between the edge pins and rotate to splay it out a bit, then tack those.

Goes by many names, MSOP, TSSOP (supposed to be 0.65mm pitch but go figure), VSSOP (usually a narrower TSSOP, but go figure), etc. Some cutesy names like SOT-23-8. And a zillion in-house designations, like US8.

Step 1: always read the datasheet. Pitch, body width and lead length (symbols e or e1, E and HE usually) are particularly important.

You may find this of interest:

If you can't solder them by iron, first try a pointier tip. I'm fond of the bent cone type for fine SMT. Else, get a hot air machine (my top preference here). You don't need solder paste (just tin the pads with the iron; though it's nice to have), but paste flux is pretty much required.

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Design 
Website: https://www.seventransistorlabs.com/ 

"bitrex"  wrote in message  
news:riFCF.24143$%o2.16158@fx31.iad... 
>I have some TinyLogic flip flops in the US8 package, having a very hard  
>time prototyping with them.  Pin spacing seems to be just a lil smaller  
>than TSSOP-8 so even with magnification I'm having a wicked hard time  
>landing them so that all pins connect up on a DIP-adapter board. They're  
>about half the size of a grain of rice... 
> 
> Any tips for this?

If you want to prototype with tiny parts you can't probe, you can always de sign your layout with test points. They only need to be a pad, but a via h ole would help keep your probe on the pad. Not hard to do and size usually isn't so important in prototypes.

--

  Rick C. 

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bitrex wrote in news:GjFCF.24144$% snipped-for-privacy@fx31.iad:

We had custom chips that we had to cut the leads on with a special die. There were a hundred or so gold leads about 1 to 1.5 cm long with each. I always had a collection of them just for ding things like this because gold takes solder so well, that the connection can happen fast enough to not sink excessive heat into the device.

Always good to have a heat gun and warm up the entire assembly area so that the heat jump is less too.

That 700 plus degree tip sinks a lot of heat really fast and can damage the chip. So use a low thermal mass tip, like the 'micro fine' varietey.

Winfield Hill wrote in news: snipped-for-privacy@drn.newsguy.com:

700 plus degrees F.

Several seconds to 'lather it up' and several more to wick it out. Not really a good method, unless you have a reel of them and like troubleshooting failure modes of unknown origin.

Or at least you must do this on a hot board. IOW, where you ramped up the assembly temp before introducing the thermal jump to reflow temps.

Those thermal cyclings at such huge twmp jumps are what cause one form of infant mortality.

snipped-for-privacy@highlandsniptechnology.com wrote in news: snipped-for-privacy@4ax.com:

Make vias as probe points.

google says, ..

Cool. I'll buy a bunch of those. I'm almost out of mine.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

mandag den 25. november 2019 kl. 16.20.45 UTC+1 skrev jla...@highlandsnipte chnology.com:

ptechnology.com:

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2.45? ouch, 11mm*11mm, places like JLCPCB will panelize with v-scor e so you could get 5 panels of 81 PCBs for a few $