technical data KK74LS138 3-to-8-line decoder/demultiplexer ordering information kk 74ls138n plastic kk 74ls138d soic t a = 0 to 7 0 c for all packages this schottky-clam ped ttl msi circu it is designed to be used in hi gh-perform ance m e m o ry -decordi ng or dat a -rout i ng appl i cat i ons requi ri ng very short propagat i on del a y t i m e. in hi gh-perform ance m e m o ry system s this decode can be used to m i nim i ze the effects of system d eco d i n g . w h en em p l o y ed with h i g h - sp eed m e m o ries u tilizin g a fast en ab le circu it th e d e lay tim es o f this decorder and the enable tim e of the m e m o ry are usually less than th e typical access tim es of the m e m o ry. th is m ean s th at th e effectiv e system d e lay in tro d u ced b y th e sch o ttk y- clam pled system decoder is negligible. ? desi gned speci fi cal l y for hi gh speed m e m o ry decoders and dat a transm ission system s ? incorporat e 3 enabl e r input s t o si m p l i f y cascadi ng and/ or dat a reception ? schot t k y c l am ped for hi gh perform ance pin assignment logic diagram pin 16 =v cc pin 8 = gnd function table input s o u t put s c s 1 c s 2 c s 3 a 2 a 1 a0 y0 y1 y2 y3 y4 y5 y6 y7 x x h x h x l x x x x x x x x x x x h h h h h h h h h h h h h h h h h h h h h h h h h l l h l l h l l h l l l l l l l h l h l l h h l h h h h h h h h l h h h h h h h h l h h h h h h h h l h h h h h l l h l l h l l h l l h l l h l h h h l h h h h h h h l h h h h h h h h l h h h h h h h h l h h h h h h h h l h = hi gh l e vel (st eady st at e) l = lo w lev e l (stead y state) x = don?t care 1
KK74LS138 maximum ratings * s y m b o l p a r a m e t e r v a l u e u n i t v cc suppl y vol t a ge 7.0 v v in input vol t a ge 7.0 v v out out put vol t a ge 5.5 v tst g st orage tem p erat ure r a nge -65 t o +150 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. recommended operating conditions s y m b o l p a r a m e t e r m i n m a x unit v cc suppl y vol t a ge 4.75 5.25 v v ih hi gh level input vol t a ge 2.0 v v il low level input vol t a ge 0.8 v i oh hi gh level out put c u rrent -0.4 m a i ol low level out put c u rrent 8.0 m a t a am bi ent tem p erat ure r a nge 0 +70 c dc electrical characteristics over full operating conditions g u a r a n t e e d l i m i t s y m b o l p a r a m e t e r t e s t c o n d i t i o n s m i n m a x unit v ik input c l am p vol t a ge v cc = m i n, i in = -18 m a -1.5 v v oh hi gh level out put vol t a ge v cc = m i n, i oh = -0.4 m a 2.7 v v ol low level out put vol t a ge v cc = m i n, i ol = 4 m a 0.4 v v cc = m i n, i ol = 8 m a 0.5 i ih hi gh level input c u rrent v cc = m a x, v in = 2.7 v 20 a v cc = m a x, v in = 7.0 v 0.1 m a i il low level input c u rrent v cc = m a x, v in = 0.4 v -0.4 m a i o out put short c i rcui t c u rrent v cc = m a x, v o = 0 v (not e 1) - 2 0 - 1 0 0 m a i cc suppl y c u rrent v cc = m a x out put s enabl e d and open 1 0 m a note 1: not m o re than one output should be shorted at a tim e, and duration should not exceed one second. 2
KK74LS138 ac electrical characteristics (t a =25 c, v cc = 5.0 v, c l = 15 pf, r l = 2 k ? , t r =15 ns, t f = 6.0 ns) s y m b o l p a r a m e t e r l e v e l m i n m a x u n i t t plh m a xi m u m propagat i on del a y , input a t o output y 2 2 0 n s t phl m a xi m u m propagat i on del a y , input a t o output y 4 1 n s t plh m a xi m u m propagat i on del a y , input a t o output y 3 2 7 n s t phl m a xi m u m propagat i on del a y , input a t o output y 3 9 n s t plh m a xi m u m propagat i on del a y , c s 1 t o output y 3 2 6 n s t phl m a xi m u m propagat i on del a y , c s 1 t o output y 3 8 n s t plh m a xi m u m out put transi t i on ti m e , c s 2 or c s 3 t o out put y 2 1 8 n s t phl m a xi m u m out put transi t i on ti m e , c s 2 or c s 3 t o out put y 3 2 n s fi gure 1. sw i t chi n g waveforms fi gure 2. sw i t chi n g waveforms notes a. c l i n cl udes probe and ji g capaci t a nce. b . al l di odes are 1n916 or 1n3064. fi gure 3. sw i t chi n g waveforms figure 4. test circuit 3
KK74LS138 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 4
|
