for:char printed on:mon, feb 6, 1995 09:49:45 from book:dl121ch4 (5) view document:mc74f381 (5) view last saved on:fri, feb 3, 1995 16:06:52
4-179 fast and ls ttl data 4-bit arithmetic logic unit the mc54/74f381 performs three arithmetic and three logic operations on two 4-bit words, a and b. t wo additional select input codes force the function outputs low or high. carry propagate and generate outputs are provided for use with the f182 carry lookahead generator for high-speed expansion to longer word lengths. for ripple expansion, refer to the f382 alu data sheet. ? low input loading minimizes drive requirements ? performs six arithmetic and logic functions ? selectable low (clear) and high (preset) functions ? carry generate and propagate outputs for use with carry lookahead generator connection diagram 18 17 16 15 14 13 1 2 3 4 5 6 7 20 19 8 v cc a 1 a 2 b 2 a 3 b 3 p c n g b 1 a 0 b 0 s 0 s 1 s 2 f 0 9 10 f 1 gnd 12 11 f 3 f 2 logic symbol 15 7 6 5 13 14 c n s 2 s 1 s 0 f 0 f 1 f 2 f 3 3 16 17 18 19 4 1 2 a 0 b 0 a 1 b 1 a 2 b 2 a 3 b 3 g p v cc = pin 20 gnd = pin 10 8 12 11 9 guaranteed operating ranges symbol parameter min typ max unit v cc supply voltage 54, 74 4.5 5.0 5.5 v t a operating ambient temperature range 54 55 25 125 c t a operating ambient temperature range 74 0 25 70 c i oh output current e high 54, 74 1.0 ma i ol output current e low 54, 74 20 ma mc54/74f381 4-bit arithmetic logic unit fast ? schottky ttl ordering information mc54fxxxj ceramic mc74fxxxn plastic mc74fxxxdw soic 20 1 j suffix ceramic case 732-03 20 1 n suffix plastic case 738-03 20 1 dw suffix soic case 751d-03
4-180 fast and ls ttl data mc54/74f381 logic diagram please note that this diagram is provided only for the understanding of logic operations and should not be used to estimate propagation delays. c n b 0 a 0 b 1 a 1 b 2 a 2 b 3 a 3 s 0 s 1 s 2 f 0 f 1 f 2 f 3 p g ovr c n +4 f381 only f382 only
4-181 fast and ls ttl data mc54/74f381 dc characteristics over operating temperature range (unless otherwise specified) symbol parameter limits unit test conditions symbol parameter min typ max unit test conditions v ih input high voltage 2.0 v guaranteed input high voltage v il input low voltage 0.8 v guaranteed input low voltage v ik input clamp diode voltage 1.2 v i in = 18 ma v cc = min v oh output high voltage 54, 74 2.5 3.4 v i oh = 1.0 ma v cc = 4.5 v v oh output high voltage 74 2.7 3.4 v i oh = 1.0 ma v cc = 4.75 v v ol output low voltage 0.35 0.5 v i ol = 20 ma v cc = min i ih input high current 20 m a v in = 2.7 v v cc = max i ih input high current 100 m a v in = 7.0 v v cc = max i il input low current s 0 s 2 inputs 0.6 ma v in = 0.5 v vcc = max i il other inputs 2.4 ma v in = 0.5 v vcc = max i os output short circuit current (note 2) 60 150 ma v out = 0 v v cc = max i cc power supply current 59 89 ma s 0 s 2 = gnd; other inputs high v cc = max notes: 1. for conditions such as min or max, use the appropriate value specified under guaranteed operating ranges. 2. not more than one output should be shorted at a time, nor for more than 1 second. functional description signals applied to the select inputs s 0 s 2 determine the mode of operation, as indicated in the function select t able. an extensive listing of input and output levels is shown in the truth t able. the circuit performs the arithmetic functions for either active-high or active-low operands, with output lev- els in the same convention. in the subtract operating modes, it is necessary to force a carry (high for active-high oper - ands, low for active-low operands) into the c n input of the least significant package. the carry generate (g ) and carry propagate (p ) outputs supply input signals to the f182 carry lookahead generator for expansion to longer word length, as shown in figure 1. note that an f382 alu is used for the most significant package. typical delays for figure 1 are given in figure 2. function select table select operation s 0 s 1 s 2 operation l l l clear h l l b minus a l h l a minus b h h l a plus b l l h a b h l h a + b l h h ab h h h preset h = high v oltage level l = low v oltage level
4-182 fast and ls ttl data mc54/74f381 select 3 3 c in a 0 a 3 b 0 b 3 a 4 a 7 b 4 b 7 a 8 a 11 b 8 b 11 a 12 a 15 b 12 b 15 4 4 g p a b c n s f f382 c n +4 ovr f 12 f 15 f 0 f 3 f 4 f 7 f 8 f 11 c n g 0 p 0 g 1 p 1 c n+y g 2 p 2 c n+z f182 cla overflow c n+z c out 3 4 4 a b c n s f f381 3 4 4 a b c n s f f381 3 4 4 a b c n s f f381 g p g p figure 1. 16-bit lookahead carry alu expansion path segment toward f output c n + 4, ovr path segment toward f output c n + 4, ovr a i or b i to p 7.2 ns 7.2 ns p i to c n + j ('f182) 6.2 ns 6.2 ns c n to f 8.1 ns e c n to c n + 4 , ovr e 8.0 ns total delay 21.5 ns 21.4 ns figure 2. 16-bit delay tabulation ac characteristics symbol parameter 54/74f 54f 74f unit symbol parameter t a = +25 c t a = 55 to +125 c t a = 0 to +70 c unit symbol parameter v cc = +5.0 v v cc = 5.0 v 10% v cc = 5.0 v 10% unit symbol parameter c l = 50 pf c l = 50 pf c l = 50 pf unit symbol parameter min typ max min max min max unit t plh propagation delay 2.5 8.1 12 2.5 15 2.5 13 ns t phl c n to f i 2.5 5.7 8.0 2.5 11 2.5 9.0 ns t plh propagation delay 4.0 10.4 15 4.0 18 4.0 16 ns t phl any a or b to any f 3.5 8.2 11 3.5 14 3.5 12 ns t plh propagation 4.5 8.3 20 4.5 23.5 4.5 21.5 ns t phl s i to f i 4.0 8.2 13 4.0 16 4.0 14 ns t plh propagation delay 3.0 6.4 9.0 3.0 12 3.0 10 ns t phl a i or b i to g 4.0 6.8 10 4.0 13 4.0 11 ns t plh propagation delay 2.5 7.2 10.5 2.5 13.5 2.5 11.5 ns t phl a i or b i to p 3.5 6.5 9.5 3.5 12.5 3.5 10.5 ns t plh propagation delay 4.0 7.8 12 4.0 15 4.0 13 ns t phl s i to g or p 4.5 10.2 13.5 4.5 16.5 4.5 14.5 ns
4-183 fast and ls ttl data mc54/74f381 truth table inputs outputs function s 0 s 1 s 2 c n a n b n f 0 f 1 f 2 f 3 g p clear 0 0 0 x x x 0 0 0 0 0 0 b minus a 1 0 0 0 0 0 1 1 1 1 1 0 b minus a 1 0 0 0 0 1 0 1 1 1 0 0 b minus a 1 0 0 0 1 0 0 0 0 0 1 1 b minus a 1 0 0 0 1 1 1 1 1 1 1 0 b minus a 1 0 0 1 0 0 0 0 0 0 1 0 1 0 1 1 1 1 1 0 0 1 1 0 1 0 0 0 1 1 1 1 1 0 0 0 0 1 0 a minus b 0 1 0 0 0 0 1 1 1 1 1 0 a minus b 0 1 0 0 0 1 0 0 0 0 1 1 a minus b 0 1 0 0 1 0 0 1 1 1 0 0 a minus b 0 1 0 0 1 1 1 1 1 1 1 0 a minus b 0 1 0 1 0 0 0 0 0 0 1 0 1 0 1 1 0 0 0 1 1 1 1 0 1 1 1 1 0 0 1 1 1 0 0 0 0 1 0 a plus b 1 1 0 0 0 0 0 0 0 0 1 1 a plus b 1 1 0 0 0 1 1 1 1 1 1 0 a plus b 1 1 0 0 1 0 1 1 1 1 1 0 a plus b 1 1 0 0 1 1 0 1 1 1 0 0 a plus b 1 1 0 1 0 0 1 0 0 0 1 1 1 0 1 0 0 0 0 1 0 1 1 0 0 0 0 0 1 0 1 1 1 1 1 1 1 0 0 a b 0 0 1 x 0 0 0 0 0 0 0 0 a b 0 0 1 x 0 1 1 1 1 1 1 1 a b 0 0 1 x 1 0 1 1 1 1 1 0 x 1 1 0 0 0 0 0 0 a+b 1 0 1 x 0 0 0 0 0 0 0 0 a+b 1 0 1 x 0 1 1 1 1 1 1 1 a+b 1 0 1 x 1 0 1 1 1 1 1 1 x 1 1 1 1 1 1 1 0 ab 0 1 1 x 0 0 0 0 0 0 0 0 ab 0 1 1 x 0 1 0 0 0 0 1 1 ab 0 1 1 x 1 0 0 0 0 0 0 0 x 1 1 1 1 1 1 1 0 preset 1 1 1 x 0 0 1 1 1 1 1 1 preset 1 1 1 x 0 1 1 1 1 1 1 1 preset 1 1 1 x 1 0 1 1 1 1 1 1 x 1 1 1 1 1 1 1 0 1 = high voltage level 0 = low voltage level x = immaterial
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