unisonic technologies co., ltd u74hc123 cmos ic www.unisonic.com.tw 1 of 10 copyright ? 2013 unisonic technologies co., ltd qw-r502-a10.a dual retriggerable monostable multivibrator with reset ? description 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 (r ext ) and capacitor (c ext ). 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, sop-16 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 d nr , which also inhibits the triggering. an internal connection from d nr to the input gates makes it possible to trigger the circuit by a positive-going signal at input d nr as shown in the function table. the basic out put pulse width is essent ially determined by the values of the external timing components r ext and c ext . schmitt-trigger action in the na 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 information ordering number package packing lead free halogen free u74hc123l-s16-r u74hc123g-s16-r sop-16 tape reel u74hc123l-s16-t u74hc123g-s16-t sop-16 tube u74hc123l-p16-r U74HC123G-P16-R tssop-16 tape reel u74hc123l-p16-t u74hc123g-p16-t tssop-16 tube
u74hc123 cmos ic unisonic technologies co., ltd 2 of 10 www.unisonic.com.tw qw-r502-a10.a pin configuration ? function table inputs outputs d nr na nb nq nq l x x l h x h x l(2) h(2) x x l l(2) h(2) h l h h l h note: 1. h: high voltage level l: low voltage level x: don?care : low-to-high transition : high-to-low transition : one high level output pulse : one low level output pulse 2. if the monostable was triggered before this condit ion was established, the pulse will continue as programmed.
u74hc123 cmos ic unisonic technologies co., ltd 3 of 10 www.unisonic.com.tw qw-r502-a10.a ? logic symbol
u74hc123 cmos ic unisonic technologies co., ltd 4 of 10 www.unisonic.com.tw qw-r502-a10.a ? logic diagram
u74hc123 cmos ic unisonic technologies co., ltd 5 of 10 www.unisonic.com.tw qw-r502-a10.a ? absolute maximum rating parameter symbol ratings unit supply voltage v cc -0.5 ~ 7 v v cc or gnd current i cc 50 ma output current i out 25 ma input clamp current i ik 20 ma output clamp current i ok 20 ma storage temperature t stg -65 ~ + 150 c note: absolute maximum ratings are those values be yond which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device oper ation is not implied. ? recommended operating conditions parameter symbol test conditions min typ max unit supply voltage v cc 2 5 6 v high-level input voltage v ih v cc =2v 1.5 1.2 v v cc =4.5v 3.15 2.4 v cc =6v 4.2 3.2 low-level input voltage v il v cc =2v 0.8 0.5 v v cc =4.5v 2.1 1.35 v cc =6v 2.8 1.8 input voltage v in 0 v cc v output voltage v out 0 v cc v input transition rise and fall rate d nr input t/ v v cc =2v 1000 ns v cc =4.5v 500 v cc =6v 400 ambient temperature t amb -40 +25 +125 c ? electrical characteristics (t a =25c , unless otherwise specified) parameter symbol test conditions min typ max unit output voltage high-level v oh v cc =2v, i oh =-20 a 1.9 2 v v cc =4.5v, i oh =-20 a 4.4 4.5 v cc =6v, i oh =-20 a 5.9 6 v cc =4.5v, i oh =-4ma 3.98 4.32 v cc =6v, i oh =-5.2ma 5.48 5.81 output voltage low-level v ol v cc =2v, i ol =20 a 0 0.1 v v cc =4.5v, i ol =20 a 0 0.1 v cc =6v, i ol =20 a 0 0.1 v cc =4.5v, i ol =4ma 0.15 0.26 v cc =6v, i ol =5.2ma 0.16 0.26 input leakage current i i ( leak ) v cc =6v, v in = v cc or gnd 0.1 a quiescent supply current i cc v cc =6v, v in =v cc or gnd, i out =0 8 a input capacitance c i 3.5 pf
u74hc123 cmos ic unisonic technologies co., ltd 6 of 10 www.unisonic.com.tw qw-r502-a10.a ? switching characteristics (t r = t f = 6ns, c l =50pf, t a =25c, unless otherwise specified) parameter symbol test conditions min typ max unit propagation delay time from na , nb to nq or nq t plh /t phl v cc =2v c ext =0pf r ext =5k 83 255 ns v cc =4.5v 30 51 v cc =5v, c l =15p 26 v cc =6v 24 43 propagation delay time from d nr to nq or nq t plh /t phl v cc =2v c ext =0pf r ext =5k 66 215 ns v cc =4.5v 24 43 v cc =5v, c l =15p 20 v cc =6v 19 37 output transition time t t v cc =2v 19 75 ns v cc =4.5v 7 15 v cc =6v 6 13 trigger pulse width na =low t w v cc =2v 100 8 ns v cc =4.5v 20 3 v cc =6v 17 2 trigger pulse width nb=high t w v cc =2v 100 17 ns v cc =4.5v 20 6 v cc =6v 17 5 reset pulse width d nr =low t w v cc =2v 100 14 ns v cc =4.5v 20 5 v cc =6v 17 4 output pulse width nq=high, nq=low t w v cc =5v , c ext =100nf, r ext =10k 450 s output pulse width nq=high, nq=low t w v cc =5v , c ext =0pf, r ext =5k 75 ns retrigger time na , nb t rt v cc =5v , c ext =0pf, r ext =5k 110 ns external timing resistor r ext v cc =2v 10 1000 k ? v cc =5v 2 1000 external timing capacitor c ext v cc =5v 2 10000 pf ? operating characteristics (t a =25c , unless otherwise specified) parameter symbol test conditions min typ max unit power dissipation capacitance per monostable c pd 54 pf
u74hc123 cmos ic unisonic technologies co., ltd 7 of 10 www.unisonic.com.tw qw-r502-a10.a ? test circuit and waveforms
u74hc123 cmos ic unisonic technologies co., ltd 8 of 10 www.unisonic.com.tw qw-r502-a10.a ? test circuit and waveforms(cont.)
u74hc123 cmos ic unisonic technologies co., ltd 9 of 10 www.unisonic.com.tw qw-r502-a10.a ? application information timing component connections the basic output pulse width is essentially determined by the values of the external timing components r ext and c ext . power-up considerations when the monostable is powered-up it may produce an output pulse, with a pulse width defined by the values of r ext and c ext , this output can be eliminated using the circuit below.
u74hc123 cmos ic unisonic technologies co., ltd 10 of 10 www.unisonic.com.tw qw-r502-a10.a ? application information(cont.) power-down considerations a large capacitor (c ext ) may cause problems when powering-down t he monostable due to the energy stored in this capacitor. when a system containing this dev ice is powered-down or a rapid decrease of v cc to zero occurs, the monostable may substain damage, due to the capacitor di scharging through the input protection diodes. to avoid this possibility, use a damping diode (d ext ) preferably a germanium or schottky type diode able to withstand large current surges and connect as shown below. utc assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all utc products described or contained herein. utc products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. the information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.
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