Revision as of 00:47, 9 July 2019

A series of various 74LS chips.

7400 series is an extended family of digital integrated circuits. Chips in this series include a variety of discrete logic chips chips such as and gates and or gates as well as registers, decoders, and RAM units.

While the original series was designed as TTL logic chips, over the years, a large number of sub-families have been introduced. Generally speaking, parts from the same subfamily can be used freely with other parts from the same subfamily. However, in many cases not with parts from other subfamilies. This is because voltage and current configurations for ICs from the same subfamily are designed so they can be connected without requiring additional work.

Part Identification

• Specs/Temp Indicator:

75 - Interface device

74 - Commercial Grade

64 - Industrial

54 - Military/Airspace Grade

• Technology indicator:

Some of more popular ones you'll encounter are:

None - When no indicator is found, this implies it's the original TTL

Bipolar

S - Schottky logic.

LS - Low-power Schottky. Same as L series but with reduced power consumption and switching speed.

CMOS

C - CMOS

AC / ACT - Advanced CMOS (T version for TTL-compatible inputs)

HC / HCT - High-speed CMOS, similar to LS (T version for TTL-compatible inputs)

AHC / AHCT - Advanced high-speed CMOS (T version for TTL-compatible inputs)

LV / LVC' - Low-Voltage CMOS

BiCMOS

BCT - BiCMOS

ABT - Advanced BiCMOS

• Gates Count (surface mount ICs only)

1G = 1, 2G = 2, 3G = 3

• Device Number

• Package Designation

Example

Chip is labeled DM74LS221N:

DM - prefix - made by Fairchild or National Semiconductor, but given the F logo, we can determine it's Fairchild.

74 - series - commercial grade chip

LS - techno - Low-power Schottky.

221 - device - Dual non-retriggerable monostable multivibrator with reset

N - package - standard plastic DIP

List of Devices

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