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What does Schottky Signify?

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Electroenthusiast

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IC7400's nomenclature contain the word "Schottky", what does it signify?
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* 74 - the "standard TTL" logic family had no letters between the "74" and the specific part number.
* 74L - Low power (compared to the original TTL logic family), very slow
* H - High speed (still produced but generally superseded by the S-series, used in 1970s era computers)
* S - Schottky (obsolete)
* LS - Low Power Schottky
* AS - Advanced Schottky
* ALS - Advanced Low Power Schottky
* F - Fast (faster than normal Schottky, similar to AS)
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Are you familiar with the difference between a Silicon diode and a Schottky diode?
 
In Schottky TTL a Schottky diode is placed between the base (anode) and collector (cathode) of all transistors that fully turn on. The low forward drop of the Schottky diode prevents the transistor from going into hard saturation (it shunts any excess base current into the collector and thus to ground). This minimizes the turn-off recovery time of the transistor, and increases the speed of the logic. Thus, for example, low-power Schottky (LS) is just about as fast as standard TTL, even though it uses significantly less power.
 
Just use the 74HC series which is CMOS so uses no power when in the static state and is faster than TTL. It also has the advantage of a wider supply voltage range of 2V to 6V which means you can use a couple of AA cells and no voltage regulator.
 
And how are IC's Named? i.e., Nomenclature of IC's >
My question is Why 7408 is 7408'?; Why not any other Number ?
Similarly 741 - OPAMP ?
 
That was Fairchild's naming protocol way back in the early days of Silicon Valley. Their devices were later licensed to other manufacturers, and the naming protocol stuck; probably through the licensing agreements. Further, the US Army and Navy were the major consumers of these devices back in the 1960's forward, and the Joint Army/Navy standards (JAN) were developed as "Military Specifications" (milspec) for purchasing these devices meeting those specifications. The same goes for the uA741, developed by D. Hilbiber at Fairchild.
 
Most early IC numbering systems were rather arbitrary. The started out with a low number and sequentially increased the numbers as the chips were designed. Thus it's likely that a 7408 was developed before a 7474. An early Fairchild op amp was a 709. Later they came out with the 741 which was the first IC op amp with internal frequency compensation (it had a 30pF capacitor integrated on the chip, which occupied a large percentage of the chip area).
 
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