74LS122 Retriggerable Monostable Multivibrator


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. 74LS122 re-triggered multivibrators feature output pulse-duration control by three methods. The basic pulse time is programmed by selection of external resistance and capacitance values (see typical application data)

74LS122 Features

  • DC Triggered Multivibrators with Pulse Width Control
  • Overriding Clear Terminates Output Pulse
  • DC Triggered from Active-High or Active-Low
  • Operating Temperature up to 70°C
  • Standard TTL Switching Voltages

74LS122 Specifications

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

74LS122 Pinout Diagram

74LS122 Pin Description

Pin NoPin NameDescription
1A1Data Input Pin A1
2A2Data Input Pin A2
3B1Data Input Pin B1
4B2Data Input Pin B2
5CLRClear Pin
6Q1 Output Pin
8Q2 Output Pin
9RintInternal Resistor
10NCNot Connected
11CextExternal Capacitor
12NCNot Connected
13Rext/CextExternal Resistor/External Capacitor
14VCCPositive Supply

74LS122 Circuit

Here is a simple monostable multivibrator circuit using 2n4401 transistors


  • Delay and timing circuits.

74LS122 Alternative Equivalent


Download 74LS122 Retriggerable Monostable Multivibrator Datasheet from the link given below.