Logic IC Families & Technologies Summary Chart

There are many different logic families or technologies available: RTL, DTL, TTL, ECL to 7400 with its modern low voltage variants

Logic IC families & Technologies Includes:
IC logic families & technolgies summary chart     Numbering schemes     7400 Series TTL    

There is a host of different types of logic ranging from the very early technologies including RTL and DTL right through the basic 7400 series and 4000 CMOS types right through to the latest low voltage high speed technologies of today.

After the introduction of the integrated circuit, IC, logic blocks were naturally contained within chips. Accordingly a variety of logic IC families spawned, each offering different capabilities and facilities.

Over the years, the most widely used overall family has been the 7400 series ICs. Initially launched as straight 7400 series integrated circuits, this logic IC family has spawned many variants which has enabled it to remain in use until this day.

Logic families chart / table

A tabulation of the major logic families with relevant data is given below. Links to further pages with more in depth information for each logic family are given within the table.

Logic IC Families & Technologies Chart
Logic Family or Series Logic Technology Supply voltage
Basic Details Link
RTL Resistor Transistor Logic ~3 The RTL logic technology was one of the very first introduced. It first was available in 1962 and as the name implies it used just resistors and transistors.
DTL Diode transistor logic 5 The DTL logic family or series used diodes on the inputs to create functions such as AND and OR and then had transistors on the output. It was soon superseded by the later TTL logic technology.
MECL I Emitter coupled logic -5.2 ECL was the first type of logic IC family to be developed and it appeared around 1962.
ECL III Emitter coupled logic -5.2
(-5.19 - -5.21)
This was an improved form of ECL - emitter coupled logic. It was very fast having toggle speeds of up to 500 MHz, but it was very current hungry and chips would run very warm. However its speed meant that it remained in use, often being used in RF applications such as frequency synthesizers where very fast counters were needed. Running from a negative supply it was difficult to interface to many other elements of the design, although interface chips were available.
ECL 10k Emitter coupled logic -5.2
(-5.19 - -5.21)
An updated version of ECL, although it had a top toggle speed of around 125 MHz
ECL 100K Emitter couple logic -5.2
(-5.19 - -5.21)
An even later version of ECL but with a maximum clock speed of 350 MHz.
7400 TTL 5
(4.75 - 5.25)
Introduced around 1964, this series of logic used transistors in all areas of the chip. It became an industry standard. This technology and its numbering scheme was adopted for many future generations of logic chip technology. The numbers fot he devices were retained such that the function contained within a 74**XX chip would remain the same across the different logic technologies. Read More
74L00 TTL (Low Power) 5
(4.75 - 5.25)
Introduced in 1964, the low power 7400 series of logic devices used lower power than the standard TTL family, but at the expense of speed and output capability.
74H00 TTL (High speed) 5
(4.75 - 5.25)
Again introduced in 1964, this high speed TTL offered a speed of almost twice that of the standard 7400 logic family, but at the expense of increased current consumption.
74S00 TTL (Schottky) 5
(4.75 - 5.25)
Using Schottky diode technology, this form of TTL was able to offer operating speeds of around four times that of the standard 7400 logic family
74LS00 TTL (Low power Schottky) 5
(4.75 - 5.25)
The low power Schottky logic family offered lower propagation delays, higher toggle speeds and lower power levels per gate than the original 7400 logic family. As such it became very widely used for many years
74ALS TTL (Advanced low power Schottky) 5
(4.5 - 5.5)
Advanced low power Schottky giving increased speed and lower power when compared to low power Schottky.
74F00 TTL (Fast) 5
(4.75 - 5.25)
Fast TTL, offering speeds that are four times that of standard 7400 series TTL. While the speed is essentially the same as Schottky TTL, it provides the speed at around a quarter of the power.

There have been many different families of logic IC and their associated technologies. As expected, the very early logic families and technologies have been discontinued, but many different logic types are available. Even though most logic is contained within larger chips these days, there is still the need to small logic functions in many circuits.

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