unisonic technologies co., ltd u74ahc245 cmos ic www.unisonic.com.tw 1 of 5 copyright ? 2013 unisonic technologies co., ltd qw-r502-987.a octal bus transceivers with 3-state outputs ? description the u74ahc245 octal bus transceivers is designed for asynchronous two-way communication between data buses. the control-function implementation minimizes external timing requirements. the device allows data transmission from the a bus to the b bus or from the b bus to the a bus, depending on the logic level at the direction-control (dir) input. the output-enable ( oe ) input can be used to disable the device so that the buses are effectively isolated. to ensure the high-impedance st ate during power up or power down, oe should be tied to v cc through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver. ? features * operating range 2v to 5.5v v cc ? ordering information ordering number package packing lead free halogen free U74AHC245L-R20-T u74ahc245g-r20-t ssop-20 tube u74ahc245l-r20-r u74ahc245g-r20-r ssop-20 tape reel
u74ahc245 cmos ic unisonic technologies co., ltd 2 of 5 www.unisonic.com.tw qw-r502-987.a ? 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; x:don?t care ? logic diagram
u74ahc245 cmos ic unisonic technologies co., ltd 3 of 5 www.unisonic.com.tw qw-r502-987.a ? absolute maximum rating parameter symbol ratings unit supply voltage v cc -0.5~7.0 v input voltage range v i -0.5~7.0 v output voltage range v o -0.5~v cc +0.5 v input clamp current (v in < 0) i ik -20 ma output clamp current (v o < 0 or v o >v cc ) i ok 20 ma output current i out 25 ma v cc or gnd current i cc 75 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 2 5.5 v input voltage v in 0 5.5 v output voltage v out 0 v cc v operating temperature t opr -40 85 c input transition rise or fall rate v cc =3.3v0.3v ? t/ ? v 100 ns/v v cc =5v0.5v 20 operating free-air temperature t a -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 =2v 1.5 v v cc =3v 2.1 v cc =5.5v 3.85 low-lever output voltage v il v cc =2v 0.5 v v cc =3v 0.9 v cc =5.5v 1.65 high-level output voltage v oh v cc =2v, i oh =-50 a 1.9 2 v v cc =3v, i oh =-50 a 2.9 3 v cc =4.5v, i oh =-50 a 4.4 4.5 v cc =3v, i oh =-4ma 2.58 v cc =4.5v, i oh =-8ma 3.94 low-level output voltage v ol v cc =2v, i ol =50 a 0.1 v v cc =3v, i ol =50 a 0.1 v cc =4.5v, i ol =50 a 0.1 v cc =3v, i ol =4ma 0.36 v cc =4.5v, i ol =8ma 0.36 input leakage current a or b inputs i i(leak) v cc =5.5v, v in =v cc or gnd 0.1 a oe or dir v cc =0 to 5.5v, v in =v cc or gnd output off-state current i oz v cc =5.5v, v out =v cc or gnd 0.25 a quiescent supply current i q v cc =5.5v, v in =v cc or gnd, i out =0 4 a input capacitance( oe or dir) c i v cc =5v, v in =v cc or gnd 2.5 10 pf input capacitance(a or b inputs) c io v cc =5v, v in =v cc or gnd 4 pf
u74ahc245 cmos ic unisonic technologies co., ltd 4 of 5 www.unisonic.com.tw qw-r502-987.a ? switching characteristics (t a =25 , r l =1k ? ,unless otherwise specified) 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 =3.3v0.3v, c l =15pf 5.8 8.4 ns v cc =3.3v0.3v, c l =50pf 8.3 11.9 v cc =5v0.5v, c l =15pf 4 5.5 v cc =5v0.5v, c l =50pf 5.5 7.5 3-state output enable time from input ( oe ) to output (a or b) t en (t pzl /t pzh ) v cc =3.3v0.3v, c l =15pf 8.5 13.2 ns v cc =3.3v0.3v, c l =50pf 11 16.7 v cc =5v0.5v, c l =15pf 5.8 8.5 v cc =5v0.5v, c l =50pf 7.3 10.6 3-state output disable time from input ( oe ) to output (a or b) t dis (t plz /t phz ) v cc =3.3v0.3v, c l =15pf 8.9 12.5 ns v cc =3.3v0.3v, c l =50pf 11.5 15.8 v cc =5v0.5v, c l =15pf 5.6 7.8 v cc =5v0.5v, c l =50pf 7 9.7 ? operating characteristics (v cc =5v, t a =25 ) parameter symbol test conditions min typ max unit power dissipation capacitance c pd no load, f=1mhz 14 pf
u74ahc245 cmos ic unisonic technologies co., ltd 5 of 5 www.unisonic.com.tw qw-r502-987.a ? test circuit and waveforms c l (note 1) from output r l v cc k1 k2 notes: 1. c l includes probe and jig capacitance. 2. all input pulses are supplied by generat ors having the following characteristics: prr 1mhz, z o =50 ? , t r 3ns, t f 3ns. 3. the outputs are measured one at a time with one input transition per measurement. figure 1. load circuit and voltage waveforms 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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