Tips on Collecting Integrated Circuits (ICs)


DIP
DIPs are dying

Perhaps you have noticed, but I have — the 50 year old DIP IC package is gradually becoming obsolete and most new IC devices do not have a DIP counterpart.
I’m not necessarily talking about the classics like the 741 or the 555, but about vast series of logic devices.

Learn from history

What happened to the 709 or the 302 operational amplifiers? What happened to RTL (resistor-transistor logic –700 series), DTL (diode-transistor logic –900 series), MHTL (Motorola high-threshold logic –600 series), and 700 series HNIL high noise immunity logic? What is happening to the 74Cxxxx series CMOS logic? And there are numerous others as well.

For a little nostalgia, check out Don Lancaster’s classic RTL Cookbook circa 1968. http://www.tinaja.com/ebooks/rtlcb.pdf (It is a 13M download). The Lunar Lander navigational computer was entirely made up of 2 input RTL gates in the vintage flatpack package.

Yes, obsolescence is normal as better and more popular stuff gradually replaces the old. How can a manufacturer run a very complex manufacturing line at a profit if the demand is low? How can distributors stock obsolete stuff when their inventory is taxed? In my mind inventory taxes are regressive. However, businesses are in the business of being profitable — that is the bottom line and they cannot be faulted for that. But now the additional issue of package obsolescence is being thrown in.

The future of electronic experimentation as we know it is at risk

Yes, in the not too distant future it will be far more difficult to breadboard experimental circuits. Small, fine pitch ICs do not lend themselves to breadboard assembly — yes, it can be done, but with great difficulty and expense. Yes, expense because obsolete stuff can usually be purchased at a price.

In working with electronic purchasing agents, I learned the expression “Raiders of the East,” in which certain firms made it their business to find out which devices were going out of production and purchasing entire stocks or getting manufacturers to make an additional final production run. This precious inventory was then resold at confiscatory profit.

DIY circuit boards may not be a good solution

Yes, circuit boards must be designed in order to use new SMD devices that have no DIP counterparts, but even the relatively crude 0.05” pitch device is a challenge for DIY techniques. However, learn this skill as where there is a need, there will be a way — DIY technology will improve with time and effort. Yes, expresspcb.com is a possible professional solution, but at $51 per design, it is generally too expensive for experimentation or where multiple iterations are required for a clean design.

There is no “Protoboard” for SMD devices — or is there?

The Protoboard is a great tool for experimenters, but without DIP devices, this assembly technique is at risk. The best you can do here is to purchase some SIP and DIP adapters from DigiKey.

At $5.88, this SIP adapter is expensive, but performs a necessary task:

SOIC to SIP adapter

http://www.digikey.com/product-detail/en/9163/9163CA-ND/151983
http://www.capitaladvanced.com/pdf%20documents/9163ids.pdf

SOIC to DIP adapter

SOIC to DIP adapter

Check out the Surfboard product line that is also available at DigiKey:
http://www.capitaladvanced.com/pdf%20documents/BULLETIN%20SI-116.pdf

Become a DIP packrat

Yes, this is my advice — collect DIP devices for use in the future. Be willing to invest a little money. I suggest that you hoard DIP 4000 series CMOS devices and DIP 74HCxxxx devices. Unneeded parts can later be used for bartering for stuff you really need. Note that eBay is a good source for small quantities of obsolete stuff, and you can sell your unneeded stuff there as well.

TO-92 devices will be next

Collect an assortment of TO-92 devices as well as new transistor offerings are in the tiny SOT-23 package.

Undocumented words and idioms (for our ESL friends)

flatpack –early IC package with ribbon leads — very thin — predates the DIP package


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