6.4 Thermal Information

THERMAL METRIC(1)

CD74HC21

UNIT

N (PDIP)

D (SOIC)

14 PINS

14 PINS

RθJA

Junction-to-ambient thermal resistance

65.2

133.6

°C/W

RθJC(top)

Junction-to-case (top) thermal resistance

52.9

89.0

°C/W

RθJB

Junction-to-board thermal resistance

44.9

89.5

°C/W

ΨJT

Junction-to-top characterization parameter

32.5

45.5

°C/W

ΨJB

Junction-to-board characterization parameter

44.7

89.1

°C/W

RθJC(bot)

Junction-to-case (bottom) thermal resistance

N/A

N/A

°C/W

(1)

For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application

report.

6.5 Electrical Characteristics

over operating free-air temperature range; typical values measured at TA = 25°C (unless otherwise noted).

PARAMETER

TEST CONDITIONS

VCC

Operating free-air temperature (TA)

UNIT

25°C

–40°C to 85°C

–55°C to 125°C

MIN

TYP

MAX

MIN

TYP

MAX

MIN

TYP

MAX

VOH

High-level

output voltage

VI = VIH or

VIL

IOH = –20

µA

2 V

1.9

1.9

1.9

V

4.5 V

4.4

4.4

4.4

6 V

5.9

5.9

5.9

IOH = –4

mA

4.5 V

3.98

3.84

3.7

IOH = –5.2

mA

6 V

5.48

5.34

5.2

VOL

Low-level output

voltage

VI = VIH or

VIL

IOL = 20

µA

2 V

0.1

0.1

0.1

V

4.5 V

0.1

0.1

0.1

6 V

0.1

0.1

0.1

IOL = 4 mA 4.5 V

0.26

0.33

0.4

IOL = 5.2

mA

6 V

0.26

0.33

0.4

II

Input leakage

current

VI = VCC or GND

6 V

±0.1

±1

±1

µA

ICC

Supply current

VI = VCC or

GND

IO = 0

6 V

2

20

40

µA

Ci

Input

capacitance

5 V

10

10

10

pF

6.6 Switching Characteristics

over operating free-air temperature range; typical values measured at TA = 25°C (unless otherwise noted).

PARAMETER

FROM

TO

TEST

CONDITIO

NS

VCC

Operating free-air temperature (TA)

UNIT

25°C

–40°C to 85°C

–55°C to 125°C

MIN TYP MAX

MIN TYP MAX

MIN TYP MAX

tpd

Propagation delay

A, B, C,

or D

Y

CL = 50 pF

2 V

110

140

165

ns

4.5 V

22

28

33

6 V

19

24

28

A, B, C,

or D

Y

CL = 15 pF 5 V

9

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CD74HC21, CD54HC21

SCHS131D – AUGUST 1997 – REVISED MAY 2021

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