1. General description
The 74AHC123A; 74AHCT123A is a dual retriggerable monostable multivibrator with reset. The
basic output pulse width is programmed by selection of external components (REXT and CEXT).
Once triggered this basic pulse width may be extended by retriggering either of the edge triggered
inputs (nA or (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. Inputs are overvoltage tolerant. This feature allows the use of
these devices as translators in mixed voltage environments.
2. Features and benefits
• Wide supply voltage range from 2.0 V to 5.5 V
• DC triggered from active HIGH or active LOW inputs
• Retriggerable for very long pulses up to 100 % duty factor
• Direct reset terminates output pulse
• Overvoltage tolerant inputs to 5.5 V
• All inputs have a Schmitt-trigger action
• High noise immunity
• Input levels:
• For 74AHC123A: CMOS level
• For 74AHCT123A: TTL level
• ESD protection:
• HBM JESD22-A114E exceeds 2000 V
• MM JESD22-A115-A exceeds 200 V
• CDM JESD22-C101C exceeds 1000 V
• Latch-up performance exceeds 100 mA per JESD 78 Class II Level A
• Multiple package options
• Specified from -40 °C to +85 °C and from -40 °C to +125 °C