Traditional 54/74 TTL Logic

Gary Dowdy

It has been awhile since I have designed with 54/74 series TTL. In the extended temperature ranges, I notice, for example, SNJ54LS02J (Note the 'J' in SNJ54) vs what I am used to seeing, SN54LS02J. What does the first 'J' in the part number represent?

over 9 years ago

0 Emrys Maier over 9 years ago

TI__Guru* 96591 points

Gary,

I found the definition in a Data Book from 1993:

SN = Standard prefix

SNJ = JEDEC Publication 101, Class B

JANB = MIL-M-38510 Qualified

It seems that JEDEC no longer uses this classification system -- to quote their rescission notification: "This document is being rescinded as it was found to be redundant with the requirements of either MIL-PRF-38535 or MIL-STD-883."

There is additional info in this previous post.

0 Gary Dowdy over 9 years ago in reply to Emrys Maier

Prodigy 50 points

Ok, I understand the 'standards' perspective that you present. Why would TI sell SNJ and SN? What market would the SNJ be best suited for that the SN series does not?

0 Emrys Maier over 9 years ago in reply to Gary Dowdy

TI__Guru* 96591 points

I'm afraid I don't know the exact applications this goes into, but the standard appears to be for the military. Generally speaking, the military has higher standards than other end users.

0 Gary Dowdy over 9 years ago in reply to Emrys Maier

Prodigy 50 points

My view is that the '54' is what designates the military temperature ranges and military standards. This is now getting to the root of my question. What is the distinction for military customers when they design with SNJ54LS02J (Note the 'J' in SNJ54) vs what I am used to seeing, SN54LS02J?

0 Richard Biddle over 9 years ago in reply to Gary Dowdy

TI__Expert 5570 points

The "54" denotes military temperature range (-55°C to +125°C unless otherwised sepcified). The "SN" prefix is commercial level. The "SNJ" prefix is MIL-SPEC (MIL-PRF-38535 QML Class Q). See www.ti.com/.../hirel_product_nomenclature.pdf for information on nomenclature.DLA Standard Microcircuit Drawings (SMD) and JAN Part Numbers FAQ.pdf

is added as an FAQ on p=DLA part numbers.

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Traditional 54/74 TTL Logic