5.5 Switching Characteristics

Input tt = 6ns. Unless otherwise specified, CL = 50pF

PARAMETER

VCC (V)

25°C

-40°C to

85°C

-55°C to

125°C

UNIT

TYP

MAX

MAX

MAX

HC TYPES

tpd

Propagation delay data to outputs

2

90

115

135

ns

4.5

7

(1)

18

23

27

6

15

20

23

tPZL, tPZH

Output high-Z, to high level to low level

2

150

190

225

ns

4.5

12

(1)

30

38

45

6

26

33

38

tPHZ, tPLZ

Output high level, output low level to

high-Z

2

150

190

225

ns

4.5

12

(1)

30

38

45

6

26

33

38

tt

Output transition times

2

60

75

90

ns

4.5

12

15

18

6

10

13

15

Ci

Input capacitance

10

10

10

pF

CO

Three-state output capacitance

20

20

20

pF

Cpd (2) (3)

Power dissipation capacitance

5

80

pF

HCT TYPES

tpd

Propagation delay data to outputs

4.5

9

(1)

22

28

33

ns

tPZH, tPLZ

Output high-Z to high level to low level

4.5

14

(1)

34

43

51

ns

tPHZ, tPLZ

Output high level, output low level to

high-Z

4.5

14

(1)

35

44

53

ns

tt

Output transition times

4.5

12

15

18

ns

Ci

Input capacitance

10

10

10

pF

CO

Three-state output capacitance

20

20

20

pF

Cpd (2) (3)

Power dissipation capacitance

5

91

pF

(1)

Typical value tested at 5V, CL = 15pF.

(2)

CPD is used to determine the dynamic power consumption, per channel.

(3)

PD = VCC 2fi (CPD + CL) where fi = Input Frequency, fO = Output Frequency, CL = Output Load Capacitance, VCC = Supply Voltage.

CD54HC243, CD74HC243, CD54HCT243, CD74HCT243

SCHS168E – NOVEMBER 1998 – REVISED MARCH 2022

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