OT - 40 years of 5 volt TTL logic

I get annoyed at how much "tarnish" accumulates on the pins over the years...

("Time to go polish the TTL...")

That would be about right for me, too! I think that was the year, 1971, when I got my TI databook on the 7400/5400 series.

And yes, TTL in the form of LS, S, AS, ALS, and F still survives. Does anyone still use/provide the original?

not to mention ... AC, ACT, HC, HCT, AHCT ...

Jon

It occurs to me that I just used a knife to cut a frayed end off of a belt that I'm resizing.

Some technologies do persist, TTL logic has a way to go before it 'edges' out blades.

Now that is funny and so true!

Jon

Seems to be still widely available - and in use too by the look of it!

HC is still very useful. I still design it into new products. 74HC595 and 74HC165 are unbeatable as low cost "I/O expanders", converting 3 microcontroller pins into an unlimited number of switched I/Os at negligible cost.

The Tinylogic style single gates are useful as "non-logic" components too, especially in the newer families like LVC, AUP. I use them for gate drivers, oscillators, PWM circuits etc.

- and 5V is making something of a come back too :) Wide supply is now common to see, not just in Logic, but also in Microcontrollers and RAM.

Of course, you can also grumble about how LITTLE TTL/CMOS series devices have changed, and how generic standards lock us into generic parts.

As an example, I was looking for a simple, selectable divider recently. Sadly, because the original 4020/40/60 designer did not think of adding a Mux, no one has done so since...

-jg

It's the latest thing with the kids:

Mel.

It made a nicer, more compact product than the Mullard Norbit I was using before moving over to TTL (probably around the same time as yourself). Before Norbit we had discrete RTL circuits. Aahhhhh; Memories!!!!

I remember when we got a device in 1974, and it was marked with batch YearYear/WeekWeek, you could end up with for example, a 7406 marked 7406 twice because of the naming and batch convention.

many a wrong IC was selected by newbies who didn't understand.

Cheers Don...

===============

-- Don McKenzie

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These products will reduce in price by 5% every month:

Bare Proto PCB for PIC or AVR projects? "I'd buy that for a Dollar!".

I remember those dark times....

rYear/WeekWeek, you could end up with for

ion.

Perhaps 5-6 years later when I got to use these things - and Bulgaria being under the then Soviet block it was often easier to get Soviet equivalents. Their naming conventions were Cyrillic, of course - which made things look funny, somehow too native (Cyrillic is the Bulgarian alphabet) where it did not belong or sort of. But on top of that what a taste for unpronounceable, ugly sounding character combinations did they have ... Yet they used to work reasonably well, OK, failed more than the "true" parts but at an acceptable rate.

Dimiter

------------------------------------------------------ Dimiter Popoff Transgalactic Instruments

------------------------------------------------------

Likewise *245 and *574 for buffers to oustide world or voltage domains rather blow a cheap TTL than the FPGA.

AHC594 for simple cascadable SPI driven n-bit port, with latched o/p.

Just done a new designs with AHC138 and some FETs for banks of relay decode. Only logic on the cards.

All over the place likewise for similar reasons. One case used an inverter between two relays for creating changeover configuration to cope with mechanical and other constraints of relays.

Huh? Any specific example, please?

I know that the conventions have changed at least (and probably exactly) once since these times (and I guess that I've never seen an IC marked the old way), but I've never seen a part with a mark that I could describe as ?ugly.? (Unpronounceable ? yes, but I don't think that HC or LS is any better.)

K2=D0=96=D0=90242 =D0=9A=D0=A0=D0=95=D0=9D5A K1111X=D0=9B1

le =E2=80=94 yes,

One good thing about soviet part naming system was that parts of similar =

classes had similar alphanumeric indexes. In the West, each company has=20 part numbering system of their own.

The quality was very dependent on particular manufacturing plant. Moscow =

and Minsk were good, Abovyan - sucks, others - watch for the=20 manufacturing date. Made in Bulgaria or East Germany were good also. You =

can open a device for repair and immediately tell which parts failed=20 just by watching factory marks on ICs.

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

Indeed, this one predates ???? 18682-73. It'd be ?224??2 under the latter instead.

That was just the lack of space to provide the full marking (which is ??142??5?; cf., e. g., 74HC-series IC's in SOIC or TSSOP cases), wasn't it? Besides, ???? is perfectly pronounceable.

Nice.

Well, yes, the general purpose (such as, e. g.,: generator, amplifier, logic, etc.) marking (a two-letter code, reasonably easy to remember) is prescribed by the standard.