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I am very familiar with the usual vendors for components, and how to select parts for a design, including package and footprints. However, I'm looking for an efficient way to track down 'throw-away" parts that we would use for tuning our pick-and-place process, without burning through the actual expensive parts we want to place.

So I literally need to filter by footprint and low price only, disregarding functional category of the part. But at the usual vendors, I don't seem to be able to start a search that omits the functional category.

For example, we want to place a part that comes in a 10-VSSOP package. Also known as 10-TFSOP, 10-MSOP; a 3mm-square body with 0.5mm pin pitch. But we'd rather not use up the actual part at a >$2 each (and short supply) getting the PnP process dialed in.

(This is for relatively short runs of 10s or 100s, where the overhead of dialing in the particular package is not amortized over a full reel.)

So I'd appreciate any ideas on how to zero in on "cheap parts having package X".

gwideman
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    Email the vendor. – DKNguyen Feb 01 '22 at 14:20
  • How much overage are you needing to dial in your process? 10pcs, 100pcs, 1000pcs? Its hard to see why this is worth the effort unless you are really desperate due to the chipocalypse. – crasic Feb 01 '22 at 14:54
  • As a point of reference for professional manufacture, on first runs, the pcba manufacturer that I work with will order 5-10 additional pieces of each part. That covers the process dial-in and also T&R losses from the tape leader/splicing. – crasic Feb 01 '22 at 15:04

3 Answers3

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Search for the package name on some dealer's web site (for example, DigiKey calls it "10-TFSOP"), go to the largest categories that are likely to have cheap chips, and then search for that package.

In this case, this results in 10-TFSOP op amps and 10-TFSOP switches.

DigiKey's search specification (s=N4Ig...) appears to be the same for all categories, so you can add it to the URL of the higher-ranking category: 10-TFSOP ICs.

CL.
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  • I appreciate your suggestion, but it's not a very quick solution. Digikey has 100+ categories, and while some have only a few members, many have a lot of members. Your method still requires visiting a lot of them, and copy-pasting the search spec, which is only slightly faster than picking the package and "in stock" from the filter UI. – gwideman Feb 01 '22 at 00:15
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There are blank IC packages, exactly for this purpose. Example: https://global.kyocera.com/prdct/semicon/semi/std_pkg/

Topline dummies: https://www.topline.tv/products.cfm

Lior Bilia
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  • I have a feeling there are "no function ICs" for the purpose I want. However (a) the link you gave is for parts of a package not yet assembled, ready to put a bare chip inside. They are not at the stage where they look line a component that you would use in a pick and place. And (b) where would would you actually buy the items that I do actually want, and are they cheaper than the cheapest findable "real" ICs of that package type. (Assuming that no-function ICs would be low volume, and thus probably more expensive.) – gwideman Feb 01 '22 at 00:00
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Personally, the question, from the perspective of proper process of electrical design and production is a little strange IME.

If you are doing the production yourself, really try to understand the process yields at each step before committing to additional experiments, because your proposed action may not save you parts. If you are needing more than 5-10 additional copies of a component to dial in the process, or using more than 1 panel worth of solder sample (non-EC) PCB, then you are burning PCB's and/or parts unnecessarily. Then, in this reduced efficiency situation, even if you do a pre run of "non-functional parts" , you will need to rereel those locations and assuming you are hand to mouth on a given part, you will still effectively lose (not be able to use , ) the first few pieces anyway due to the tape leader. Overall the situation is unpleasant but there is not much benefit in the 10-100 quantity to change the basic process and introduce this additional step. Of course, maybe the situation is unique or there are other constraints/issues that you are not sharing.

Assuming there is no other way to manage the situation @CL.'s answer is spot on, in this kind of corner case, over-optimized, external and ephemeral constraint caused by the economic situation i.e. emergency situation, there is no SOP. A little manual searching is the solution if the tools are not cooperating. Burning through 10 hours of digikey searches and making a spreadsheet to get an answer is a small price to pay if your critical component is out of stock globally, its just part of the job.

a few additional points

"Tuning Pick-n-place Process" - generally unfamiliar with this as a standard step for production flow, pick-n-place machines do need to be calibrated and in good order. However, I would think, even if the production line is in house, this is the job of the production lead, and shouldn't require your fancy assemblies to do it.

"Tuning in the solder process" from stencil to reflow is important if I want to transfer the process to other producers down the road, or if there are problems with yield or early failures. For example, improper stencil aperture or placement induced cracking. But if I am doing only 100 pieces, there isn't enough volume to do the study.

crasic
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  • Thanks for your effort. You've discussed scenarios that don't apply to our case, and consequently most of your answer is off-target. (We do, in fact, know about spreadsheets, and how feeders work.) So I think it' safe to summarize your answer, relative to my original question, as "supporting CL's reply". But like I say, thanks for going to the effort of contributing your thoughts. – gwideman Feb 02 '22 at 01:45
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    It's rough out there in the chipocalypse. – crasic Feb 02 '22 at 04:50