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Identifying ICs Answered

Hey everybody, I have a bunch of ICs lying around, about 50 of them, and I have no clue what any of them do. I've googled a few of them, without great results... What I'm wondering is: Does a website exist that has just a bunch of datasheets on ICs? AND, when I search for them, what item number do I use? Most have a 2 different strings, one with 5 characters and the other with more... Thanks!

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Goodhart

9 years ago

And to add to the confusion: TTL = transistor, transistor logic
as opposed to CMOS which means complementary metal-oxide semiconductor

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westfw

9 years ago

As you say, the first problem is to separate the actual part number (if present) from other data that may be printed on the chip (typically a date code of some kind, and/or other manufacturing information.) This particular set of chips is "easy" because they have the "standard" string mm74fffNNNpp, a famous set of "TTL" part numbers that were standardized "back in the day" and continue to be used even for modern parts. The next step is to translate mm74fffNNNpp into something that will turn up on google, etc. "mm" is a prefix usually related to the manufacturer. "DM" as seen in your chips was National Semiconductor, IIRC. "SN" might show up on TI chips, "HT" on Hitachi, etc. "fff" is the logic family. On the original 74xx series chips, this wasn't present at all, but as technology changed additional families were added. You can pretty much count on a 7404 (standard TTL) being function and pinout compatible with a 74hc04 (high speed comos) and a 74ls04 (low power schottkey) You have "S" (Schottky - a high speed, high power logic family) and "ALS" (Advanced Lowpower Schottky), which is similar (probably lower power.) The "pp" part of number tends to designate packaging. "N" frequently means a DIP package... So googling for 74181, 7405, and 74299 should get you pointers to data sheets.

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gmoon

9 years ago

Those are all TTL-type designations--they begin with 74. There are expanded versions of the TTL line (like schottky, for instance), and they have additional letters crammed in after the 74. A schottky-type 7408 is labeled 74S08.

For an unadorned description of the chip, just search for the 74xxx designation. The three pictured chips are:
74181, 7405, and 74299

A google search for each will surely turn up lots of datasheets (google TTL also, for an explaination of Transistor-Transistor Logic.)

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whatsisface

9 years ago

findchips.com can have varying results, I just usually google stuff.