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There are a couple of ICs that I can't find a supplier for in the UK - not carried by farnell and the uk dealer/importer doesn't want to deal in low volume, or there isn't a uk dealer/importer. There are also a couple of ICs that I think are ridiculously overpriced, so I'm looking to find them cheaper elsewhere.

Whenever I google the part numbers, it keeps coming up with a couple of online ic advertising websites/middlemen - I won't name them right now, but you know who I mean.

Has anyone had any success with either these middlemen or going direct to CN/HK/TW for certain parts?

Pol.


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You're absolutely right that it's often easier to substitute or design around a hard to find part. There is also a part of me that's a bit of a perfectionist that doesn't want to compromise when there may be a workable solution with just a bit more effort. That's why I asked the question I did, rather than "where can a find a such-and-such".

However, as you so kindly asked, I'm looking for the M54564 or TLC59213 source drivers (for a price comparison with the UDN2981), MBI5168 (for a price comparison with the TLC5916) and the DM163 (because with the TLC5940 I don't need 12-bit resolution and I do want to drive RGB LEDs, and at £3.30 each they're kinda pricey)

These are mostly components that are included in the published schematics for the Colorduino and Rainbowduino, so it's a shame that they're so difficult to find or expensive. This is especially true of the current source drivers as these can be simply replaced by p-chan FETs to switch the high side.

Pol.
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I wouldn't go quite as far as to say I think it's magic - It's just that different people put their own preference on a huge number of different factors when designing a circuit. These factors will include component price, if, and by how much, a component is overspecified; package type, lead time, minimum order quantities, ease of use, and so many more.

For me ease of use and package type are probably the most important factors - I'm going to prefer an octal sourcing driver in a through hole package over 8 individual surface mount FETs as I'll be hand soldering to a prototyping board - with overspecification and price being my perfectionist ideals. (Note that I'm not looking for the NXP LED drivers, as they are only available in surface packages, while the DM163 comes in a DIP flavour)

For the Colourduino/Rainbowduino people, they are going to have a different set of priorities, and they are going to focused on getting the BOM down as much as possible - smaller SMT components, automated assembly, reduced price (economies of scale), possibly concerned about guaranteeing future availability/lead times.

OTOH, 8-unit sourcing drivers are remarkably rare considering how useful they are for driving arrays. M54564FP is available from iTead at US$3.50 which, I agree, seems remarkably steep.  I've looked for octal sourcing drivers before and didn't even find M54564FP.

And this is what I find so counter intuitive - the demand for these items exists even if it's only for the hobbyist market (worst case, it's only you and me looking for them) so why are they so uncommon and seemingly overpriced when you can find them? Maybe I should test the capitalist theories but buying 20 or so from the far east and putting them up on ebay to see how well they sell...

Pol.
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Quote
I'm going to prefer an octal sourcing driver in a through hole package over 8 individual surface mount FETs
That is why they are increasingly becoming expensive. Few people in industry use anything but surface mount and the numbers of hobbyists are so tiny that it is not sufficient to sustain any sort of market.
I well known chip manufacturer recently withdrew an amplifier chip because of lack of demand when I tried to order 20,000 of them. They never got beyond the available in samples stage. They wanted an order for a minimum of two million before they would consider making them.
When you consider how fast things move it is not surprising that distributors like Farnell  and RS can't afford to carry everything.

As a general rule approach the official distributor for a manufacturers device and ask them who they sell it to so you can track down a supply.
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