The beauty of ICs

December 03, 2015

David Ashton-December 03, 2015

Regular readers will have gathered that I am an inveterate hoarder of all things electronic, and (as a subset of the above) a devoted scavenger of parts off old boards.   Occasionally I come across Integrated Circuits on old boards for which I will have no possible use, but which are unusual enough in appearance that I will keep them and perhaps even disassemble them further, if that is possible. This is a short slideshow of some of the more unusual – and, I think, beautiful - ICs I have come across in my meanderings, which may bring happy memories to some readers who may have dealt with them (or even designed them) in the past, and smiles of disbelief to younger ones who have not had the privilege of working with these old through-hole components.

Take this monster. It consists of a square ceramic base nearly 3 inches on the side, with 3 separate big SMD ICs mounted on it, along with a few SMD capacitors and one resistor. So I guess technically it’s a hybrid circuit, not an IC per se, but it is pretty…. One of the ICs has a round heatsink mounted on it like a helipad. It came out of an old server. It has a paper label affixed to it proclaiming itself to be a CYM7232S40HGC, and the brief datasheet I found on the net for it tells me that it is a DRAM Accelerator module, with 64-bit data busses and 32-bit error correction. It apparently had a big brother, the CYM7264, which did 64-bit error correction. 371 pins (my count) and a huge socket came with it. The datasheet is dated 1995 and there is what might be a date code of 3993 (1993; week 39) on the label.

More ceramics
Of course many of the original through-hole Large-Scale Integration (LSI) ICs that came out were on ceramic carriers; you don’t see them much any more. A lot of the original microprocessors came with a ceramic option and the sight of one never fails to lift my heart, for some reason. I think ceramic packages were more temperature stable and used for parts specified for larger temperature ranges? Here is an old ULA (Uncommitted Logic Array) – the forerunner of todays FPGAs. I got a few of these and by judicious heating I managed to take the metal lid off one of them exposing the chip and connecting wires inside.

Standard 40-pin format, but a nice geometric looking chip inside and that lovely bonding strip across the top of the IC.   My USB microsope is only 1.3 Megapixels, alas, but here’s what the chip looks like at that resolution:

Continue to the next page: That's not an IC - THIS is an IC! >>


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