74LS21 Dual 4-input AND Gate


The 74LS series of integrated circuits (ICs) was one of the most popular logic families of transistor-transistor logic (TTL) logic chips. 74LS series is a bipolar, low-power Schottky IC. 74LS21 Dual 4-input AND Gate contain two independent 4-input AND gates

74LS21 Features

  • Two Independent AND Gates
  • Standard Pin Configuration
  • Fast Switching Times
  • Operating Temperature up to 70°C
  • Standard TTL Switching Voltages

74LS21 Specifications

Supply Voltage4.75 – 5.25Vdc
Maximum Clock Frequency40Mhz
Power Dissipation2mW/gate @100kHz
Minimum Output Current8mA
Propagation Delay10nS
Fan Out (TTL Loads)20

74LS21 Pinout Diagram

74LS21 Pin Description

Pin NoPin NameDescription
1A1AND Gate 1 Input 1
2B1 AND Gate 1 Input 2
3NCNO Connection
4C1 AND Gate 1 Input 3
5D1 AND Gate 1 Input 4
6X1 AND Gate 1 Output
8X2 AND Gate 2 Output
9A2 AND Gate 2 Input 1
10B2 AND Gate 2 Input 2
11NCNo Connection
12C2 AND Gate 2 Input 3
13D2 AND Gate 2 Input 4
14VCCPositive Supply

74LS21 Circuit


  • Data transmission control in digital electronics.
  •  Alarm circuits.

74LS21 Alternative Equivalent

74LS08, 74LS09, 74LS11

Download 74LS21 Dual 4-input AND Gate Datasheet from the link given below.