SN54xx and SN84xx chips?

If memory serves, SN54xx are function and pin equivalents of SN74xx. I think the differences are packaging and temperature range. SN54xx that I've seen were ceramic DIPs and had wider temperature range. Equip. I worked on in the Air Force often used SN54xx.

SN54xxx chips are exactly the same as SN74xxx chips, except for the tremperature range specs. 54 series is military temperature range, guaranteed to function from -55C to +125C. You will see that some of them are slightly slower than some of the commercial chips, but they are hardier so it's worth it if you need the broader operating range. Standard 74 series chips are only guaranteed to operate from 0C to 70C if memory serves.

The 54xx series is usually the "military grade" - Identical in every way except temperature range they can be safely/reliably operated in, to the corresponding 74xx chip. Sometimes, depending on the exact chip you're looking at, they're a tad slower than the corresponding 74xx chip, but they do the same job, using the same pins in the same positions, etc, and survive higher (and lower) temps than 74xx chips can cope with. For

74xx/53xx, as long as the tmeperature that you expect them to operate in is within the specs for both, you can mix and match them, swap one for the other, etc, without any noticable difference (other than the "sometimes" speed difference noted above, which *MIGHT* be big enough to "bite" you if you're doing circuits that are fast enough to notice the difference.)

I've never encountered an 84xx chip, but I would presume that they're the same way, only in yet another temp. range, or perhaps have a different speed or voltage rating.

--
Don Bruder - dakidd@sonic.net - New Email policy in effect as of Feb. 21, 2004.
I respond to Email as quick as humanly possible. If you Email me and get no 
response, see  Short
form: I'm trashing EVERYTHING that doesn't contain a password in the subject.

I'd guess that the lower speed only appears at on of the temperature extremes, and that at eual temperature the speed will be more or less the same. Or?

Thomas

Well, not exactly "identical in every way except temperature range". Enough speculation; I pulled down the dusty 1972 Signetics digital databook: supply voltage (S5490) - 4.5v, min. 5.5v, max supply voltage (N7490) - 4.75v, min. 5.25v, max.

Short circuit output current and supply current are also different. Further than that I ain't gonna look.

From a very old ITT data book, in the Texas Instruments section... 74 series: 0ºC to +70ºC 64 series: -40ºC to +80ºC 54 series: -55ºC to +125ºC Same pin-outs and functions, different temperature range.

Not sure about 84 series, I cannot find them listed anywhere.

Some others I have found listed in that old book... 9N series: TTL - as 74 series. 660 series: HTL logic. 830 series: DTL logic. 930 series: DTL logic. 1800 series: DTL logic. 8000 and 80L00 series TTL. 9930 series: DTL logic. MC10000 series: ECL logic.

Versions of TTL families

Commercial U(industrial): SN74.... 0 °C..+70 °C

Extended industrial: SN84.... -25 °C..+85 °C

Military: SN54.... -55 °C..+125 °C