74AHCT123AD,112

74AHC123A 74AHCT123A Dual retriggerable monostable multivibrator with reset Rev. 4 8 November 2011 Product data sheet 1. General description The 74AHC123A 74AHCT123A 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 74AHCT123A 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 (R ) and capacitor (C ). The external resistor and EXT EXT capacitor are normally connected as shown in Figure 11. 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 as shown in Table 3. Figure 8 and Figure 9 illustrate pulse control by retriggering and early reset. The basic output pulse width is essentially determined by the value of the external timing components R and C . When EXT EXT C 10 nF, the typical output pulse width is defined as: t =R C where EXT W EXT EXT t = pulse width in ns R = external resistor in k C = external capacitor in pF. W EXT EXT Schmitt-trigger action at all inputs makes the circuit highly tolerant to slower input rise and fall times. 2. Features and benefits All inputs have a Schmitt-trigger action Inputs accept voltages higher than V CC DC triggered from active HIGH or active LOW inputs Retriggerable for very long pulses up to 100 % duty factor Direct reset terminates output pulse For 74AHC123A only: operates with CMOS input levels For 74AHCT123A only: operates with TTL input levels ESD protection: HBM JESD22-A114E exceeds 2000 V MM JESD22-A115-A exceeds 200 V CDM JESD22-C101C exceeds 1000 V Multiple package options Specified from 40 C to +85 C and from 40 C to +125 C74AHC123A 74AHCT123A Nexperia Dual retriggerable monostable multivibrator with reset 3. Ordering information Table 1. Ordering information Type number Package Temperature range Name Description Version 74AHC123AD 40 C to +125 C SO16 plastic small outline package 16 leads SOT109-1 body width 3.9 mm 74AHCT123AD 74AHC123APW 40 C to +125 C TSSOP16 plastic thin shrink small outline package 16 leads SOT403-1 body width 4.4 mm 74AHCT123APW 74AHC123ABQ 40 C to +125 C DHVQFN16 plastic dual in-line compatible thermal enhanced SOT763-1 very thin quad flat package no leads 16 terminals 74AHCT123ABQ body 2.5 3.5 0.85 mm 4. Functional diagram 14 CX 15 RCX 13 1 & 14 1CEXT 2 6 2CEXT 15 1REXT/CEXT 4 7 2REXT/CEXT 3 R S 13 1Q Q 6 5 2Q CX 1A 1 T 7 2A 9 RCX 5 4 1Q Q 9 1B 2 & 12 2Q 2B 10 10 RD 1RD 3 12 2RD 11 11 R 001aae521 001aae522 Fig 1. Logic symbol Fig 2. IEC logic symbol 74AHC AHCT123A All information provided in this document is subject to legal disclaimers. Nexperia B.V. 2017. All rights reserved Product data sheet Rev. 4 8 November 2011 2 of 22