unisonic technologies co., ltd u74hct245 cmos ic www.unisonic.com.tw 1 of 5 copyright ? 2012 unisonic technologies co., ltd qw-r502-646.b octal bus transceivers with 3-state outputs ? description the u74hct245 is designed for the asynchronous communication between data buses. while the direction-control(dir) is high, dat a transmits from the a bus to the b bus. data transmits from the b bus to the a bus if dir is low. the output-enable ( oe ) will isolate the device from the buses when high voltage is applied on it. ? features * operate from 4.5v to 5.5v * typical t pd is 14ns at 5.5v * inputs are ttl voltage compatible sop-20 ssop-20 tssop-20 ? ordering information ordering number package packing lead free halogen free u74hct245l-p20-r u74hct245g-p20-r tssop-20 tape reel u74hct245l-p20-t U74HCT245G-P20-T tssop-20 tube u74hct245l-r20-r u74hct245g-r20-r ssop-20 tape reel u74hct245l-r20-t u74hct245g-r20-t ssop-20 tube u74hct245l-s20-r u74hct245g-s20-r sop-20 tape reel u74hct245l-s20-t u74hct245g-s20-t sop-20 tube
u74hct245 cmos ic unisonic technologies co., ltd 2 of 5 www.unisonic.com.tw qw-r502-646.b ? pin configuration ? function table input function oe dir h x isolation l h transmit data from a bus to b bus l l transmit data from b bus to a bus note: h: high voltage level; l: low voltage level. ? logic diagram
u74hct245 cmos ic unisonic technologies co., ltd 3 of 5 www.unisonic.com.tw qw-r502-646.b ? absolute maximum rating parameter symbol ratings unit supply voltage v cc -0.5~7.0 v input clamp current (v in < 0) i ik 20 ma output clamp current (v out < 0) i ok 20 ma output current i out 35 ma v cc or gnd current i cc 70 ma storage temperature t stg -65 ~ +150 c notes: 1. absolute maximum ratings are those values beyond which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device oper ation is not implied. 2. the input and output voltage ratings may be ex ceeded if the input and output current ratings are observed. ? recommended operating conditions parameter symbol min typ max unit supply voltage v cc 4.5 5 5.5 v input voltage v in 0 v cc v output voltage v out 0 v cc v input transition rise or fall rate t t 500 ns operating temperature t opr -40 85 c ? electrical characteristics (t a =25 , unless otherwise specified) parameter symbol test conditions min typ max unit high-level input voltage v ih v cc =4.5v~5.5v 2.0 1.6 v low-level output voltage v il v cc =4.5v~5.5v 1.2 0.8 v high-level output voltage v oh v cc =4.5v, i oh =-20 a 4.4 4.499 v v cc =4.5v, i oh =-6ma 3.98 4.3 v low-level output voltage v ol v cc =4.5v, i ol =20 a 0.001 0.1 v v cc =4.5v, i oh =6ma 0.17 0.26 v input current of dir or oe i i(leak) v cc =5.5v, v in =v cc or gnd 0.1 100 na output off -state current i oz v cc =5.5v, v out =v cc or gnd 0.01 0.5 a quiescent supply current i cc v cc =5.5v, v in =v cc or gnd, i out =0 8 a additional quiescent supply current i cc v cc =5.5v,one input at 0.5v or 2.4v,other inputs at 0 or v cc 1.4 2.4 ma input capacitance of dir or oe c in v cc =5.5v, v in =v cc or gnd 3 10 pf
u74hct245 cmos ic unisonic technologies co., ltd 4 of 5 www.unisonic.com.tw qw-r502-646.b ? switching characteristics (t a =25 , r l =1k ? ,unless otherwise specified) c l =50pf parameter symbol test conditions min typ max unit propagation delay from input (a or b) to output (b or a) t pd (t plh /t phl ) v cc =4.5v 16 22 ns v cc =5.5v 14 20 ns 3-state output enable time from input ( oe ) to output (a or b) t en (t pzl /t pzh ) v cc =4.5v 25 46 ns v cc =5.5v 22 41 ns 3-state output disable time from input ( oe ) to output (a or b) t dis (t plz /t phz ) v cc =4.5v 26 40 ns v cc =5.5v 23 36 ns output transition time, (a or b) t t (t r /t f ) v cc =4.5v 9 12 ns v cc =5.5v 8 11 ns c l =150pf parameter symbol test conditions min typ max unit propagation delay from input (a or b) to output (b or a) t pd (t plh /t phl ) v cc =4.5v 20 30 ns v cc =5.5v 18 27 ns 3-state output enable time from input ( oe ) to output (a or b) t en (t pzl /t pzh ) v cc =4.5v 36 59 ns v cc =5.5v 30 53 ns output transition time, (a or b) t t (t r /t f ) v cc =4.5v 17 42 ns v cc =5.5v 14 38 ns ? operating characteristics parameter symbol test conditions ratings unit power dissipation capacitance c pd no load 40 pf
u74hct245 cmos ic unisonic technologies co., ltd 5 of 5 www.unisonic.com.tw qw-r502-646.b ? test circuit and waveforms note : c l includes probe and jig capacitance. p rr 1mhz, z o = 50 ? , t r 6ns, t f 6ns 1.3v 1.3v 1.3v 1.3v 3v 0v v oh v ol propagation delay times 1.3v 1.3v 3v 0v 1.3v 10% 1.3v 90% 0v v oh v cc v ol enable and disable times a/b b/a b/a b/a oe 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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