page_title: 7400-series integrated circuits
section_title: Second sources from Europe and Eastern Bloc
hierarchical_section_title: 7400-series integrated circuits / Second sources from Europe and Eastern Bloc
caption_attribution_description: Electronic component - four typical logical (TTL) gates: Czechoslovak MH74S00, Texas Instruments SN74S251N, East German DL004D (74LS04), Soviet K155LA13 (7438)
context_page_description: The 7400 series of integrated circuits were one of the most popular logic families of transistor–transistor logic logic chips. In 1964, Texas Instruments introduced the first members of their ceramic semiconductor package series, the SN5400s. A low-cost plastic package SN7400 series was introduced in 1966 which quickly gained over 50% of the logic chip market, and eventually becoming de facto standardized electronic components. Over the decades, many generations of pin-compatible descendant families evolved to include support for low power CMOS technology, lower supply voltages, and surface mount packages.
context_section_description: Some manufacturers, such as Mullard and Siemens, had pin-compatible TTL parts, but with a completely different numbering scheme; however, data sheets identified the 7400-compatible number as an aid to recognition.
  At the time the 7400 series was being made, some European manufacturers (that traditionally followed the Pro Electron naming convention), such as Philips/Mullard, produced a series of TTL integrated circuits with part names beginning FJ. Some examples of FJ series are:
  FJH101 (=7430) single 8-input NAND gate,
  FJH131 (=7400) quadruple 2-input NAND gate,
  FJH181 (=7454N or J) 2+2+2+2 input AND-OR-NOT gate.
  The Soviet Union started manufacturing TTL ICs with 7400-series pinout in the late 1960s and early 1970s, such as the K155ЛA3, which was pin-compatible with the 7400 part available in the United States, except for using a metric spacing of 2.5 mm between pins instead of the 0.1 inches (2.54 mm) pin-to-pin spacing used in the west.
  Another peculiarity of the Soviet-made 7400 series was the packaging material used in the 1970s–1980s. Instead of the ubiquitous black resin, they had a brownish-green body colour with subtle swirl marks created during the moulding process. It was jokingly referred to in the Eastern Bloc electronics industry as the "elephant-dung packaging", due to its appearance.
  The Soviet integrated circuit designation is different from the Western series:
  the technology modifications were considered different series and were identified by different numbered prefixes – К155 series is equivalent to plain 74, К555 series is 74LS, etc.;
  the function of the unit is described with a two-letter code followed by a number:
  the first letter represents the functional group – logical, triggers, counters, multiplexers, etc.;
  the second letter shows the functional subgroup, making the distinction between logical NAND and NOR, D- and JK-triggers, decimal and binary counters, etc.;
  the number distinguishes variants with different number of inputs or different number of elements within a die – ЛА1/ЛА2/ЛА3 (LA1/LA2/LA3) are 2 four-input / 1 eight-input / 4 two-input NAND elements respectively (equivalent to 7420/7430/7400).
  Before July 1974 the two letters from the functional description were inserted after the first digit of the series. Examples: К1ЛБ551 and К155ЛА1 (7420), К1ТМ552 and К155ТМ2 (7474) are the same ICs made at different times.
  Clones of the 7400 series were also made in other Eastern Bloc countries:
  Bulgaria (Mikroelektronika Botevgrad) used a designation somewhat similar to that of the Soviet Union, e.g. 1ЛБ00ШМ (1LB00ShM) for a 74LS00. Some of the two-letter functional groups were borrowed from the Soviet designation, while others differed. Unlike the Soviet scheme, the two or three digit number after the functional group matched the western counterpart. The series followed at the end (i.e. ШМ for LS). Only the LS series is known to have been manufactured in Bulgaria.
  Czechoslovakia (TESLA) used the 7400 numbering scheme with manufacturer prefix MH. Example: MH7400. Tesla also produced industrial grade (8400, −25 ° to 85 °C) and military grade (5400, −55 ° to 125 °C) ones.
  Poland (Unitra CEMI) used the 7400 numbering scheme with manufacturer prefixes UCA for the 5400 and 6400 series, as well as UCY for the 7400 series. Examples: UCA6400, UCY7400. Note that ICs with the prefix MCY74 correspond to the 4000 series (e.g. MCY74002 corresponds to 4002 and not to 7402).
  Hungary (Tungsram, later Mikroelektronikai Vállalat / MEV) also used the 7400 numbering scheme, but with manufacturer suffix – 7400 is marked as 7400APC.
  Romania (I.P.R.S.) used a trimmed 7400 numbering with the manufacturer prefix CDB (example: CDB4123E corresponds to 74123) for the 74 and 74H series, where the suffix H indicated the 74H series. For the later 74LS series, the standard numbering was used.
  East Germany (HFO) also used trimmed 7400 numbering without manufacturer prefix or suffix. The prefix D (or E) designates digital IC, and not the manufacturer. Example: D174 is 7474. 74LS clones were designated by the prefix DL; e.g. DL00
caption: Czechoslovak MH74S00, Texas Instruments SN74S251N, East German DL004D (74LS04), Soviet K155LA13 (7438)
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