7400 Series - Second Sources in Europe and The Eastern Bloc

Second Sources in Europe and The Eastern Bloc

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 pin-out in late 1960s and early 1970s. Part numbering is different from the Western series:

• the technology modifications were considered different series, and were identified by different numbered prefixes - 155 series is equivalent to plain 74, 131 series is 74H, 158 series is 74L, 531 series is 74S, 555 series is 74LS, and 1530/1531/1533 are 74F/74AS/74ALS respectively. CMOS elements with TTL pin-out are also available, for example 1564 series is equivalent to 74HC.
• 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 plain 7400 series were also made in other Eastern Bloc countries

• Poland and Czechoslovakia used the 7400 numbering scheme with manufacturer prefixes UCY and MH respectively. Examples: UCY7400, and MH7400.
• Hungary also used the 7400 numbering scheme but with manufacturer suffix - 7400 is marked as 7400APC.
• Romania used trimmed 7400 numbering with own manufacturing prefix CDB. Example: CDB4123E is 74123.
• East Germany 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 D2; e.g. D200 = 74LS00. In later years East German made clones were also available with standard 74* numbers, usually for export.

No information is available for technology modifications (74H, 74LS, etc.) manufactured outside USSR.