74HC123 Datasheet – Monostable Multivibrator – Philips

Part Number : 74HC123

Function : Dual retriggerable monostable multivibrator with reset

Package : SOP 16 Pin

Manufactures : Philips

Image :


Description :

The 74HC/HCT123 are high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL (LSTTL). They are specified in compliance with JEDEC standard no. 7A.
The 74HC/HCT123 are dual retriggerable monostable multivibrators with output pulse width control by three methods. The basic pulse time is programmed by selection of an external resistor (REXT) and capacitor (CEXT). The external resistor and capacitor are normally connected as shown in Fig.6.
Once triggered, the basic output pulse width may be extended by retriggering the gated active
LOW-going edge input (nA) or the active HIGH-going edge input (nB). By repeating this process, the output pulse period (nQ = HIGH, nQ = LOW) can be made as long as desired. Alternatively an output delay can be terminated at any time by a LOW-going edge on input nRD, which also inhibits the triggering.


• DC triggered from active HIGH or active LOW inputs
• Retriggerable for very long pulses up to 100% duty factor
• Direct reset terminates output pulse
• Schmitt-trigger action on all inputs except for the reset input
• Output capability: standard (except for nREXT/CEXT)
• ICCcategory: MSI

Pinout and Function Table

74HC123 Datasheet

74HC123 Datasheet



Other data sheets within the file : 74HC123D, 74HC123DB, 74HC123N, 74HC123PW

54LS123 Datasheet PDF – Monostable Multivibrator – TI

Part Number : 54LS123

Function : Retriggerable Monostable Multivibrator

Package : 16 Pin Type

Manufacturers : Texas Instruments

Pinouts :

54LS123 datasheet


Description :

These d-c 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). The ‘122 and ‘LS122 have internal timing resistors that allow the circuits to be used with only an external capacitor, if so desired. Once triggered, the basic pulse duration may be extended by retriggering the gated low-level-active (A) or high-level-active (B) inputs, or be reduced by  se of the overriding clear.


1. D-C Triggered from Active-High or Active-Low Gated Logic Inputs
2. Retriggerable for Very Long Output Pulses, Up to 100% Duty Cycle
3. Overriding Clear Terminates Output Pulse

Official Homepage : http://www.ti.com/product/SN54LS123

Other data sheets within the file : SN54LS123J, 54123 LS123, SN54123J

54LS123 Datasheet PDF Download

54LS123 pdf