Practical Electronics/7400 Series/Labelling

74 and 54 Series ICs all have a code on the top of the carrier body. This can be printed (usually in white) or etched. It consists of a "core" code which identifies the IC's function, and the type of electronics used within it. This is often supplemented by manufacturer's prefixes and suffixes which give information about the manufacturer and the carrier's physical form.

Core CodeEdit

Device FamilyEdit

Device TypeEdit

Code Meaning
(none) Standard TTL
N Standard TTL
L Low-power TTL
S Schottky TTL
LS Low-power Schottky TTL
AS Advanced Schottky TTL
ALS Advanced Low-power Schottky TTL
F Fast TTL
HC High-speed CMOS, inputs CMOS compatible
HCT High-speed CMOS, inputs TTL compatible
AC Advanced CMOS, inputs CMOS compatible
ACT Advanced CMOS, inputs TTL compatible
AHC Advanced High-speed CMOS, inputs CMOS compatible
AHCT Advanced High-speed CMOS, inputs TTL compatible
LV Low-voltage CMOS
LVC Low-voltage CMOS
ALVC Advanced Low-voltage CMOS, inputs CMOS compatible
ALVT Advanced Low-voltage CMOS, inputs TTL compatible
AUC Advanced Ultra-Low-voltage CMOS
AUP Advanced Ultra-Low-power CMOS
AVC Advanced Very-Low-voltage CMOS Logic
GTLP Gunning Transceiver Logic Plus
ABT Advanced BiCMOS
LVT Low-Voltage BiCMOS
ALB Advanced Low-Voltage BiCMOS
ABTE Advanced BiCMOS / Enhanced Transceiver Logic
FB Backplane Transceiver Logic
GTL Gunning Transceiver Logic
HSTL High-speed Transceiver Logic
SSTL Stub Series Terminated Logic
SSTU Stub Series Terminated Logic (Ultra-Low-voltage)
SSTV Stub Series Terminated Logic (Very-Low-voltage)

Device FunctionEdit

This code tells you what the IC does. There are hundreds of these codes. Many common ones are given on the 74 Series page.

Manufacturer InformationEdit


This tells you which company made the IC. There a many hundred of different prefixes, and dozens of manufacturers, some sharing the same prefix. As these prefixes are not unique to the 74 Series of ICs, these prefixes are listed separately and can be found here.


This tells you the type of package that the IC comes in, for example a DIP. It can also give information about the material (e.g. ceramic or plastic). These suffixes are not unique to the 74 Series of ICs, and as such, they are listed on a separate page, here.