Datasheet

 
   
      
SCHS275E − MARCH 2002 − REVISED OCTOBER 2003
13
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
’HC190, ’HC191 timing requirements over recommended operating free-air temperature range
(unless otherwise noted) (see Figure 4)
V
CC
T
A
= 25°C
T
A
= −55°C
TO 125°C
T
A
= −40°C
TO 85°C
UNIT
V
CC
MIN MAX MIN MAX MIN MAX
UNIT
2 V 6 4 5
f
clock
Clock frequency
†
4.5 V
30 20 25
MHz
f
clock
Clock frequency
†
6 V 35 23 29
MHz
2 V 80 120 100
LOAD low
4.5 V 16 24 20
t
w
Pulse duration
LOAD low
6 V 14 20 17
ns
t
w
Pulse duration
2 V 100 150 125
ns
CLK high or low
4.5 V 20 30 25
CLK high or low
6 V 17 26 21
2 V 60 90 75
Data before LOAD↑
4.5 V 12 18 15
Data before LOAD↑
6 V 10 15 13
2 V 60 90 75
t
su
Setup time CTEN before CLK↑
4.5 V 12 18 15
ns
t
su
Setup time
CTEN before CLK↑
6 V 10 15 13
ns
2 V 90 135 115
D/U before CLK↑
4.5 V 18 27 23
D/U before CLK↑
6 V 15 23 20
2 V 2 2 2
Data before LOAD↑
4.5 V 2 2 2
Data before LOAD
6 V 2 2 2
2 V 2 2 2
t
h
Hold time CTEN before CLK↑
4.5 V 2 2 2
ns
t
h
Hold time
CTEN before CLK
6 V 2 2 2
ns
2 V 0 0 0
D/U before CLK↑
4.5 V 0 0 0
D/U before CLK
6 V 0 0 0
2 V 60 90 75
t
rec
Recovery time LOAD inactive before CLK↑
4.5 V 12 18 15
ns
t
rec
Recovery time
LOAD inactive before CLK↑
6 V 10 15 13
ns
†
Applies to noncascaded operation only. With cascaded counters, clock-to-terminal count propagation delays, CTEN
-to-clock setup times, and
CTEN
-to-clock hold times determine maximum clock frequency. For example, with these HC devices:
f
max
(
CLK
)
+
1
CLK-to-MAXńMIN propagation delay ) CTEN
-to-CLK setup time ) CTEN-to-CLK hold time
+
1
42 ) 12 ) 2
[ 18 MHz