CD54HC190, CD74HC190

CD54HC191, CD74HC191, CD54HCT191, CD74HCT191

SYNCHRONOUS UP/DOWN COUNTERS WITH DOWN/UP MODE CONTROL

SCHS275E − MARCH 2002 − REVISED OCTOBER 2003

13

POST OFFICE BOX 655303

’HC190, ’HC191 timing requirements over recommended operating free-air temperature range

(unless otherwise noted) (see Figure 4)

VCC

TA = 25°C

TA = −55°C

TO 125

°C

TA = −40°C

TO 85

°C

UNIT

VCC

MIN

MAX

MIN

MAX

MIN

MAX

UNIT

2 V

6

4

5

fclock

Clock frequency†

4.5 V

30

20

25

MHz

fclock

Clock frequency†

6 V

35

23

29

MHz

2 V

80

120

100

LOAD low

4.5 V

16

24

20

tw

Pulse duration

LOAD low

6 V

14

20

17

ns

tw

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

tsu

Setup time

CTEN before CLK

↑

4.5 V

12

18

15

ns

tsu

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

th

Hold time

CTEN before CLK

↑

4.5 V

2

2

2

ns

th

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

trec

Recovery time

LOAD inactive before CLK

↑

4.5 V

12

18

15

ns

trec

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:

+

1

CLK-to-MAX MIN propagation delay

) CTEN-to-CLK setup time ) CTEN-to-CLK hold time

+

1

42

) 12 ) 2 [

18 MHz