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7400 series

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

      Package Designation
     Device Number
    Gates Count
   Technology Indicator
  Specs/Temp Indicator
 Manufacturer Prefix
  • 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
S - Schottky logic.
LS - Low-power Schottky. Same as L series but with reduced power consumption and switching speed.
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
ABT - Advanced BiCMOS
  • Gates Count (surface mount ICs only)
1G = 1, 2G = 2, 3G = 3
  • Device Number
00 - NAND
02 - NOR
04 - NOT
08 - AND
10 - 3-input NAND
11 - 3-input AND
20 - 4-input NAND
21 - 4-input AND
25 - 4-input NOR
27 - 3-input NOR
30 - 8-input NAND
32 - 2-input OR
etc.. (full list below)
  • Package Designation
N - Plastic DIP
T - Flat package


Circuito integrado DM74LS221M.jpg

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

Device Number Description
7400 Quad 2-Input NAND Gate
7401 Quad 2-Input NAND Gate; Open-Collector Outputs
7402 Quad 2-Input NOR Gate
7403 Quad 2-Input NAND Gate; Open-Collector Outputs
7404 Hex Inverter
7405 Hex Inverter; Open-Collector Outputs
7406 Hex Inverter; Open-Collector, High Voltage Outputs
7407 Hex Buffer; Open-Collector, High Voltage Outputs
7408 Quad 2-Input AND Gate
7409 Quad 2-input AND Gate; Open-Collector Outputs
7410 Triple 3-Input NAND Gate
7411 Triple 3-Input AND Gate
7412 Triple 3-Input NAND Gate; Open-Collector Outputs
7413 Dual 4-Input NAND Schmitt triggers
7414 Hex Schmitt-Trigger Inverter
7415 Triple 3-Input AND Gate; Open-Collector Outputs
7416 Hex Inverter/Driver; Open-Collector, 15V Outputs
7417 Hex Buffer/Driver; Open-Collector, 15V Outputs
7418 Dual 4-Input NAND Gate; Schmitt-Trigger Inputs
7419 Hex Schmitt-Trigger Inverter
7420 Dual 4-Input NAND Gate
7421 Dual 4-Input AND Gate; Open-Collector, 15V Outputs
7422 Dual 4-Input NAND Gate; Open-Collector, 15V Outputs
7423 Dual 4-Input NOR Gate with Strobe
7424 Quad 2-Input NAND Gate; Schmitt-Trigger Inputs
7425 Dual 4-Input NOR Gate with Strobe
7426 Quad 2-Input NAND Gate; Open-Collector, 15V Outputs
7427 Triple 3-Input NOR Gate
7428 Quad 2-Input NOR Gate
7430 8-Input NAND Gate
7431 Hex Delay Elements
7432 Quad 2-Input OR Gate
7433 Quad 2-Input NOR Gate; Open-Collector Outputs
7434 Hex Non-Inverter
7435 Hex Non-Inverter; Open-Collector Outputs
7436 Quad 2-Input NOR Gate (Different pinout)
7437 Quad 2-Input NAND Gate (Different pinout)
7438 Quad 2-Input NAND Gate; Open-Collector Outputs
7439 Quad 2-Input NAND Gate; Open-Collector Outputs (Different pinout)
7440 Dual 4-Input NAND Gate
7447 BCD to 7-Segment Decoder/Driver; Open-Collector Outputs
7474 Dual Positive-Edge-Triggered D Flip-Flops; Preset, Clear and Complimentary Outputs
7486 Quad 2-Input XOR Gate
74112 Dual Negative-Edge-Triggered J-K Flip-Flop; Preset, Clear and Complimentary Outputs
74138 3-Line to 8-Line Decoders/Demultiplexers
74151 8-Input Multiplexer
74191 Synchronous 4-Bit Up/Down Counter with Mode Control
74194 4-Bit Bidirectional Universal Shift Register
74244 Octal 3-State Buffer/Line Driver/Line Receiver
74245 Octal Bus Transceivers with 3-State Outputs
74283 4-Bit Binary Full Adder with Fast Carry
74373 Octal Transparent Latch with 3-State Outputs; Octal D-Type Flip-Flop with 3-State Outputs
74390 Dual 4-Bit Decade and Binary Counters
74595 8-Bit Shift Registers with 3-State Output Registers
74612 Memory Mappers