74HC123N

74HC123 74HCT123 Dual retriggerable monostable multivibrator with reset Rev. 8 16 December 2011 Product data sheet 1. General description The 74HC123 74HCT123 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 74HC123 74HCT123 are dual retriggerable monostable multivibrators with output pulse width control by three methods: 1. The basic pulse is programmed by selection of an external resistor (R ) and EXT capacitor (C ). EXT 2. 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. 3. An internal connection from nRD to the input gates makes it possible to trigger the circuit by a HIGH-going signal at input nRD as shown in the function table. Schmitt-trigger action in the nA and nB inputs, makes the circuit highly tolerant to slower input rise and fall times. The 74HC123 74HCT123 are identical to the 74HC423 74HCT423 but can be triggered via the reset input. 2. Features and benefits 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 ESD protection: HBM JESD22-A114F exceeds 2000 V MM JESD22-A115-A exceeds 200 V Specified from 40 Cto+85 C and from 40 Cto+125 C74HC123 74HCT123 NXP Semiconductors Dual retriggerable monostable multivibrator with reset 3. Ordering information Table 1. Ordering information Type number Package Temperature range Name Description Version 74HC123N 40 C to +125 C DIP16 plastic dual in-line package 16 leads (300 mil) SOT38-4 74HCT123N 74HC123D 40 C to +125 C SO16 plastic small outline package 16 leads SOT109-1 body width 3.9 mm 74HCT123D 74HC123DB 40 C to +125 C SSOP16 plastic shrink small outline package 16 leads SOT338-1 body width 5.3 mm 74HCT123DB 74HC123PW 40 C to +125 C TSSOP16 plastic thin shrink small outline package 16 leads SOT403-1 body width 4.4 mm 74HCT123PW 74HC123BQ 40 C to +125 C DHVQFN16 plastic dual in-line compatible thermal enhanced SOT763-1 very thin quad flat package no leads 16 terminals body 2.5 3.5 0.85 mm 4. Functional diagram 14 1CEXT 15 1REXT/CEXT S 13 1Q Q 1 1A T 4 1Q Q 2 1B RD 3 1RD 6 2CEXT 7 2REXT/CEXT S 5 2Q Q 9 2A T 12 Q 2Q 10 2B RD 11 2RD 001aaa610 Fig 1. Functional diagram 74HC HCT123 All information provided in this document is subject to legal disclaimers. NXP B.V. 2011. All rights reserved. Product data sheet Rev. 8 16 December 2011 2 of 25