Datasheet

 
    
SCLS121D − DECEMBER 1982 − REVISED OCTOBER 2003
7
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
timing requirements over recommended operating free-air temperature range (unless otherwise
noted)
V
CC
T
A
= 25°C SN54HC191 SN74HC191
UNIT
V
CC
MIN MAX MIN MAX MIN MAX
UNIT
2 V 4.2 2.8 3.3
f
clock
Clock frequency
4.5 V
21 14 17
MHz
f
clock
Clock frequency
6 V 24 16 19
MHz
2 V 120 180 150
LOAD low
4.5 V 24 36 30
t
w
Pulse duration
LOAD low
6 V 21 31 26
ns
t
w
Pulse duration
2 V 120 180 150
ns
CLK high or low
4.5 V 24 36 30
CLK high or low
6 V 21 31 26
2 V 150 230 188
Data before LOAD↑
4.5 V 30 46 38
Data before LOAD↑
6 V 25 38 32
2 V 205 306 255
CTEN before CLK↑
4.5 V 41 61 51
t
su
Setup time
CTEN before CLK↑
6 V 35 53 44
ns
t
su
Setup time
2 V 205 306 255
ns
D/U before CLK↑
4.5 V 41 61 51
D/U before CLK↑
6 V 35 53 44
2 V 150 225 190
LOAD inactive before CLK↑
4.5 V 30 45 38
LOAD inactive before CLK↑
6 V 25 38 32
2 V 5 5 5
Data after LOAD↑
4.5 V 5 5 5
Data after LOAD↑
6 V 5 5 5
2 V 5 5 5
t
h
Hold time
CTEN
after CLK↑
4.5 V 5 5 5
ns
t
h
Hold time
CTEN after CLK↑
6 V 5 5 5
ns
2 V 5 5 5
D/U after CLK↑
4.5 V 5 5 5
D/U after CLK
6 V 5 5 5