technical data IN74HCT157A quad 2-input data selectors/multiplexer high-performance silicon-gate cmos ordering information in74hc t 157an pl ast i c in74hc t 157ad soic t a = -55 t o 125 c for all packages the in74hc t 157a i s i d ent i cal i n pi nout t o t h e ls/ a ls157. thi s device m a y be used as a level c onverter for interfacing ttl or nmos out put s t o hi gh speed c m os i nput s. thi s devi ce rout es 2 ni bbl es (a or b ) t o a si ngl e port (y) as det e rm i n ed by t h e sel ect i nput . the dat a i s present e d at t h e out put s i n noni nvert ered form . a hi gh l e vel on t h e out put enabl e i nput set s al l four y out put s t o a l o w l e vel . ? ttl/nmos com p atible input levels ? outputs directly interf ace to cmos, nmos, and ttl ? operat i ng vol t a ge r a nge: 4.5 t o 5.5 v ? low input c u rrent : 1.0 a pin assignment logic diagram pin 16 =v cc pin 8 = gnd function table input s o u t put s out put enable s e l e c t y 0 - y 3 h x l l l a 0 - a 3 l h b 0 - b 3 x=don?t care a0 -a3 , b0 -b3 = th e lev e ls o f th e resp ectiv e dat a -w ord input s rev. 00
IN74HCT157A maximum ratings * sym b o l p a r a m e t e r valu e un i t v cc dc suppl y vol t a ge (referenced t o gnd) -0.5 t o +7.0 v v in dc input vol t a ge (referenced t o gnd) -1.5 t o v cc +1.5 v v out dc output voltage (referenced to gnd) -0.5 to v cc +0.5 v i in dc input c u rrent , per pi n 20 ma i out dc out put c u rrent , per pi n 25 ma i cc dc suppl y c u rrent , v cc and gnd pins 50 ma p d po wer dissip a tio n in still air, plastic dip+ soic package+ 750 500 mw tst g st orage tem p erat ure -65 t o +150 c t l lead tem p erat ure, 1 m m from c a se for 10 seconds (plastic dip or soic package) 260 c * m a xi m u m r a t i ngs are t hose val u es bey ond whi c h dam a ge t o t h e devi ce m a y occur. functional operation should be restricted to the reco m m e nded operating conditions. +derat i ng - pl ast i c dip: - 10 m w / c from 65 t o 125 c soic package: : - 7 m w / c from 65 t o 125 c recommended operating conditions sy m bol p a r a m e t e r m i n m a x uni t v cc dc suppl y vol t a ge (referenced t o gnd) 4.5 5.5 v v in , v out dc input vol t a ge, out put vol t a ge (referenced t o gnd) 0 v cc v t a operat i ng tem p erat ure, al l package ty pes -55 +125 c t r , t f input r i se and fal l ti m e (fi gure 1 0 500 ns thi s devi ce cont ai ns prot ect i on ci rcui t r y t o guard agai ns t dam a ge due t o hi gh st at i c vol t a ges or el ect ri c fi el ds. however, precautions m u st be taken to avoid applications of any voltage highe r than m a xim u m rated voltages to this hi gh-i m pedance ci rcui t . for proper operat i on, v in and v out shoul d be const r ai ned t o t h e range gnd (v in or v out ) v cc . unused i nput s m u st al way s be t i e d t o an appropri a t e l ogi c vol t a ge l e vel (e.g., ei t h er gnd or v cc ). unused out put s m u st be l e ft open. rev. 00
IN74HCT157A dc electrical characteristics (voltages referenced to gnd) v cc guaranteed lim it sy m bol p a r a m e t e r test c ondi t i o n s v 25 c to -55 c 85 c 125 c unit v ih m i ni m u m hi gh- level input vol t a ge v out =0.1 v or v cc -0.1 v ? i out ? 20 a 4.5 5.5 2.0 2.0 2.0 2.0 2.0 2.0 v v il m a x i mu m l o w - level input vol t a ge v out =0.1 v or v cc -0.1 v ? i out ? 20 a 4.5 5.5 0.8 0.8 0.8 0.8 0.8 0.8 v v oh m i ni m u m hi gh- level out put vol t a ge v in =v ih or v il ? i out ? 20 a 4.5 5.5 4.4 5.4 4.4 5.4 4.4 5.4 v v in =v ih or v il ? i out ? 4.0 m a 4.5 3.98 3.84 3.7 v ol m a x i mu m l o w - level out put vol t a ge v in =v ih or v il ? i out ? 20 a 4.5 5.5 0.1 0.1 0.1 0.1 0.1 0.1 v v in =v ih or v il ? i out ? 4.0 m a 4.5 0.26 0.33 0.4 i in m a xi m u m input leakage current v in =v cc or gnd 5.5 0.1 1.0 1.0 a i cc m a x i mu m q u i e s c e n t suppl y c u rrent (per package) v in =v cc or gnd i out =0 a 5.5 4 . 0 4 0 1 6 0 a ? i cc ad d itio n a l qu iescen t suppl y c u rrent v in =2.4 v, any one input v in =v cc or gnd, other input s -55 c 2 5 c to 125 c ma i out =0 a 5.5 2 . 9 2 . 4 rev. 00
IN74HCT157A ac electrical characteristics (v cc =5.0 v 10%, c l =50pf,input t r =t f =6.0 ns) g u a r a n t e e d lim i t sym b o l p a r a m e t e r 25 c to -55 c 85 c 125 c unit t plh , t phl m a xi m u m propagat i on del a y , input a or b t o out put y (fi gures 1and 4) 2 7 3 4 4 1 n s t plh , t phl m a xi m u m propagat i on del a y , sel ect t o out put y (fi gures 2 and 4) 3 7 4 6 5 6 n s t plh , t phl m a xi m u m propagat i on del a y , out put enabl e t o out put y (fi gures 3 and 4) 3 0 3 8 4 5 n s t tlh , t thl m a xi m u m out put transi t i on ti m e , any out put (fi gures 1 and 4) 1 5 1 9 2 2 n s c in m a xi m u m input c a paci t a nce 10 10 10 pf power dissipation capacitance (per transceiver c h annel ) typical @25 c,v cc =5.0 v c pd used t o det e rm i n e t h e no-l o ad dy nam i c power consum pt i on: p d =c pd v cc 2 f+i cc v cc 6 4 p f fi gure 1. sw i t chi n g waveforms fi gure 2. sw i t chi n g waveforms fi gure 3. sw i t chi n g waveforms figure 4. test circuit rev. 00
IN74HCT157A expanded logic diagram rev. 00
IN74HCT157A n s u f f i x p l as t i c di p (m s - 0 0 1 b b ) sy m b o l m i n m a x a 18. 67 19. 69 b 6. 1 7 . 1 1 c 5. 33 d 0. 36 0. 56 f 1. 14 1. 78 g h j 0 10 k 2. 92 3. 81 no t e s : l 7. 62 8. 26 1. d i m e n s i o n s ?a ?, ?b ? d o n o t i n cl u d e m o l d f l as h o r p r o t r u s i o n s . m 0. 2 0 . 3 6 m a x i m u m m o l d f l a s h o r p r o t r u s i o n s 0. 25 m m ( 0 . 010) p e r s i d e . n 0. 38 d su f f i x so i c (m s - 0 1 2 a c) sy m b o l m i n m a x a 9. 8 1 0 b 3. 8 4 c 1. 35 1. 75 d 0. 33 0. 51 f 0. 4 1 . 2 7 g h j 0 8 no t e s : k 0. 1 0 . 2 5 1. d i m e n s i o ns a a n d b d o no t i n c l ud e m o l d f l a s h o r p r ot r u s i on . m 0. 19 0. 25 2. m a x i m u m m o l d f l a s h o r p r o t r u s i o n 0. 15 m m ( 0 . 006) p e r s i d e p 5. 8 6 . 2 fo r a ; fo r b ? 0. 25 m m ( 0 . 010) p e r s i d e . r 0. 25 0. 5 5. 72 2. 54 7. 62 1. 27 d i me n s i o n , mm d i me n s i o n , mm a b h c k c m j f m p g d r x 4 5 se a t i n g pl an e 0 . 25 ( 0 . 010 ) m t -t - 1 16 8 9 l h m j a b f g d se a t i n g pl a n e n k 0. 2 5 ( 0 . 010) m t -t - c 1 16 8 9 rev. 00
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