Wht is 7400 series and 741 ?

The logic that starts with the number 74 are all parts in the TTL (transistor-transistor-logic) family, that have compatible input and output signals. This family is further subdivided into groups, based on improvements in chip technology that either lowered the supply current or increased the speed, or both. The 74L family uses less current. The 74S series uses more current, but is much faster, because of the addition of Schottky diode feedback that prevents transistor saturation. The 74LS family is a compromise that uses the Schottky diodes but lowered the supply current. The 74F series was a much faster chip process, etc.

The opamp named 741 just got a number that was an arbitrary choice, and has nothing to do with the 74 logic family.

It just occurred to me, I have no idea where either the 7400 series came from, or where the 700 series of analog numbers came from, but here is a better history of TTL logic than I gave, if you are interested.

If I recall correctly, the 74xx was Texas Instruments designation for their commerical-grade TTL. They also had a parallel 54xx sereies for their MIL-spec parts.

The =B5A7xx series came from Farichild. Some other memorable members of this family were the =B5A702 and =B5A709 op-amps, =B5A711 comparator, =B5A739 dual preamp, =B5A747 (dual =B5A741 in a single package). =B5A741 was just the next one in the series.

But why did they select 74 and 54 for these purposes? That is=20 essentially the crux of the original question. I think the answer is=20 something like that your parents used in selecting your name.

f 41

Now, tell me who decided uA7xx would be the series designation and why=20 they made this choice.

I think this is pretty close to correct. Those were probably just the next blocks of numbers not being used by that company. Other companies had logic families (such as RTL and DTL) that are now forgotten. Other companies had TTL logic with other numbering systems. The 74xx nomeclature survived because of the poplarity of TI's TTL series. Eventually, even CMOS gave up most of its own numbering system and pinouts and was assimilated.

With the possible exceptions of the LM309 and LM317, who remembers the linear regulators that competed with the 78xx and 79xx sereis? In this case, I think that the descriptive way the numbers were assigned to the

78xx, plus the range of popular values, led to the dominance of this series and its offspring (the 79xx seiies obviously qualifes as offspring).

thnks every body for answering., As you told john 74XX is for commercial purpose. And 54XX is for military application. Device in 74XX series works over a temprature range 0 to 70'C and over supply range 4.75V to 5.25 Volts. And in

54XX series it works on Temp range -55 to 125'C and Supply range 4.5V to 5.5Volts. I think that answer is in its Ranges . like for 74XX series first digit(not 0 ,but 7) of temp range and first digit of

voltage range (4) makes 74. and similiarly for 54XX series first digit for temp is 5 and first digit for Vol. is 4.

I think(not sure) this could be answer of my question .Wht do you think?

Wazim Shaikh

Random numerical coincidences do not usually capture reality. If they did, numerology would be science. By the way, there was a short lived

64 series that covered the industrial temperature range -25 to +85 C). How does your hypothesis account for this?

I think the real answer came out of some marketing meeting, where they looked at what numbers were already taken for similar things and tried out how new numbers sounded. In other words, it was a totally arbitrary choice that means nothing.

74XXX series stands for LSI TTL chips. 8XXX is for MSI, TTL chips.

prateek