I'm a bit curious when the classic MC34063 IC was introduced, today available as the -A version (MC34063A).

I'm trying to get an idea when some of the classic switching controller ICs were introduced because it marks the point when switchers started to become ubiquitous.

It appears that 1975-1977 were the years when the allegedly first PWM controller IC, SG1524, was developed and introduced into the market (IEEE, Power Electronics Magazine, NASA - pdf, p. 468). To get a better idea, I am also interested in other ICs that were and are widely used, like the MC34063(A).

If I read the available information correctly, it was Motorola (now OnSemi) who first made this part, and it was or is also available from competitors such as Sipex, TI, ST, Fairchild and some smaller ones I've never heard before. Some of these just seem to have slapped their logo on top of the original data sheet, copying even the original scope screenshot along with the typical data diagrams B34063A, UTCMC34063A, HTC, MC34063, CP34063A. Looking at all these cross-references (knock offs?!), one could get the idea that the original design team is invited to feel very honored, loosely quoting Confucius.

The earliest individual Motorola Data Sheet I could find is Rev 5, dated 1996 and the device is also listed in Motorola's Linear / Interface ICs Device Data Book, Vol. 1, Rev. 4, 1993, but it's not a new device in this source either.

1990 seems to mark the upgrade from the MC34063 to the MC34063A: In Motorola's Linear & Interface IC Data Book, 1990, the MC34063 is listed as "Not For New Deisgn-Ins", and the -A version's data is printed on the following pages.

I couldn't find any earlier sources, and I don't have any early data books by Motorola on my shelves. Any sources, preferably with pdf download links, are welcome!

  • 2
    \$\begingroup\$ This question appears to be off-topic because it is not about electronic design. \$\endgroup\$ Aug 6, 2013 at 9:41
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    \$\begingroup\$ ... however, it is about the history of our profession, and there even appears to be a tag for this type of question. \$\endgroup\$
    – zebonaut
    Aug 6, 2013 at 10:49
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    \$\begingroup\$ Sometimes it's good to have a sense of the history of electronics. We've talked about vacuum tubes and even the ancient 555 timer here before, so I don't see this is being off topic. \$\endgroup\$ Aug 6, 2013 at 12:11
  • \$\begingroup\$ On thing that confuses me in the MC34063 datasheet is why is there a uA78S40 mentioned there as well. I can't imagine the same company adding (or maybe removing) a diode and an uncommitted opamp and calling the product something completely different. I'm not sure who cloned who. \$\endgroup\$
    – Fizz
    Nov 15, 2015 at 21:26

1 Answer 1


The 1983 edition of Motorola's "Linear and Interface Integrated Circuits" (Series D) catalog contains an "Advance Information" data sheet for the MC34063 so that is likely to be around the time of introduction. That catalog also contains several other switching regulator ICs. Among those were MC3420 and MC1723 (below).

My first switching regulator circuit was around 1982 using an LM723 (National Semiconductor) which could be used as a linear or a switching regulator. This part was also available from Motorola as MC1723.

Both the LM723 and the MC34063 are still available!

In 1968, Motorola published "Semiconductor Power Circuits Handbook" which contains several discreet switching regulator circuits. We have a first-edition copy where I work ... a nice little book.

For more on the history of switching supplies: https://en.wikipedia.org/wiki/Switched-mode_power_supply#History

  • \$\begingroup\$ The 34063 is used by the millions in ultracheap Chinese 12V-to-5V converters. Compared to more modern switchers its performance is rather lousy, but for these manufacturers only price counts. \$\endgroup\$
    – Johan.A
    Aug 6, 2013 at 14:45
  • \$\begingroup\$ Fairchild's uA78S40 existed in 1985 and according to that article it was popular back then, alongside NE5560N and LM352? [probably LM3524]. But I'm not sure if uA78S40 or the MC34063 came first. Nowadays there share the same datasheet at ON. \$\endgroup\$
    – Fizz
    Nov 15, 2015 at 21:36
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    \$\begingroup\$ @RespawnedFluff ... The same 1983 Motorola catalog "Linear and Interface Integrated Circuits" (Series D) contains a datasheet for uA78S40 and it is NOT "Advance Information" which would imply that it did indeed come before the MC34063. I don't have too much old Fairchild stuff on the shelf. \$\endgroup\$
    – Tut
    Nov 16, 2015 at 14:04
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    \$\begingroup\$ Aha, so it looks like they first cloned/second-sourced the Fairchild one and then decided that the extra amp isn't all that used. By the way, I incorrectly stated the uA78S40 and MC34063 share the same ON datasheet; that's not actually the case, but they share the same appnote: AN920. \$\endgroup\$
    – Fizz
    Nov 16, 2015 at 14:24

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