U74HC123

UNISONIC TECHNOLOGIES CO., LTD U74HC123 DUAL RETRIGGERABLE MONOSTABLE MULTIVIBRATOR WITH RESET SOP-16  DESCRIPTION CMOS IC The U74HC123 is high-speed Si-gate CMOS device and is pin compatible with low power Schottky TTL (LSTTL). The U74HC123 is a dual retriggerable monostable multivibrator with output pulse width control by three methods. The basic pulse time is programmed by selection of an external resistor (REXT) and capacitor (CEXT). Once triggered, the basic output pulse width may be extended by retriggering the gated active LOW-going edge input( n A ) or the active HIGH-going edge input (nB). By repeating this process, TSSOP-16 the output pulse period (nQ=HIGH, n Q =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 gates makes it possible to trigger the circuit by a positive-going signal at input nRD as shown in the function table. The basic output pulse width is essentially determined by the values of the external timing components REXT and CEXT. Schmitt-trigger action in the n A and nB inputs, makes the circuit highly tolerant to slower input rise and fall times.  FEATURES * 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  ORDERING...