74AHCT123ABQ-Q100 PCB Symbol, Footprint & ECAD Model

The 74AHC123A-Q100; 74AHCT123A-Q100 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 74AHC123A-Q100; 74AHCT123A-Q100 are dual retriggerable monostable multivibrators with output pulse width control by three methods. The selection of an external resistor (R_ext) and capacitor (C_ext) program the basic pulse time.

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.

An internal connection from nRD to the input gate makes it possible to trigger the circuit by a positive-going signal at input nRD. The values of the external timing components R_ext and C_ext, determine the basic output pulse width. When C_ext ≥ 10nF, the typical output pulse width is defined as: t_W=R_extxC_ext where t_W = pulse width in ns; R_ext = external resistor in kΩ; C_ext = external capacitor in pF. Schmitt-trigger action at all inputs makes the circuit highly tolerant to slower input rise and fall times.

This product has been qualified to the Automotive Electronics Council (AEC) standard Q100 (Grade 1) and is suitable for use in automotive applications.