5.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)(1)

SN54AHCT240

SN74AHCT240

UNIT

MIN

MAX

MIN

MAX

VCC

Supply voltage

4.5

5.5

4.5

5.5

V

VIH

High-level input voltage

2

2

V

VIL

Low-level Input voltage

0.8

0.8

V

VI

Input voltage

0

5.5

0

5.5

V

VO

Output voltage

0

VCC

0

VCC

V

IOH

High-level output current

–8

–8

mA

IOL

Low-level output current

8

8

mA

TA

Operating free-air temperature

–55

125

–40

125

°C

(1)

All unused inputs of the device must be held at VCC or GND to ensure proper device operation. See the Implications of Slow or

Floating CMOS Inputs application report.

5.4 Thermal Information

THERMAL METRIC(1)

SN74AHCT240

UNIT

DW (SOIC)

DB (SSOP)

N (PDIP)

NS (SOP

PW (TSSOP)

20 PINS

20 PINS

20 PINS

20 PINS

20 PINS

RθJA

Junction-to-ambient thermal

resistance

81.1

99.9

54.9

80.4

116.8

°C/W

RθJC(top)

Junction-to-case (top) thermal

resistance

48.9

61.7

41.7

46.9

58.5

RθJB

Junction-to-board thermal

resistance

53.8

55.2

35.8

47.9

78.7

ψJT

Junction-to-top characterization

parameter

19.5

22.6

27.9

19.9

12.6

ψJB

Junction-to-board characterization

parameter

53.1

54.8

35.7

47.5

77.9

(1)

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

5.5 Electrical Characteristics

over recommended operating free-air temperature range (unless otherwise noted)

PARAMETER

TEST CONDITIONS

TA = 25°C

SN54AHCT240

–40°C to 85°C

SN74AHCT240

–40°C to 125°C

SN74AHCT240

UNIT

MIN

TYP

MAX

MIN

MAX

MIN

MAX

MIN

MAX

VOH

High-level

output voltage

IOH = –50 µA, VCC = 4.5 V

4.4

4.5

4.4

4.4

4.4

V

IOH = –8 mA, VCC = 4.5 V

3.94

3.8

3.8

3.8

VOL

Low-level

output voltage

IOL = 50 µA, VCC = 4.5 V

0.1

0.1

0.1

0.1

V

IOL = 8 mA, VCC = 4.5 V

0.36

0.44

0.44

0.44

IOZ

High-

impedance-

state output

current

VO = VCC or GND

VCC = 5.5 V

±0.25

±2.5

±2.5

±2.5

µA

II

Inflection-

point current

VI = 5.5 V or GND

VCC = 0 V to 5.5 V

±0.1

±1(1)

±1

±1

µA

ICC

Supply

current

VI = VCC or GND

IO = 0,VCC = 5.5 V

4

40

40

40

µA

ΔICC (2)

Supply

current

change

One input at 3.4 V

other inputs at VCC or

GND

VCC = 5.5 V

1.35

1.5

1.5

1.5

mA

Ci

Input

capacitance

VI = VCC or GND

VCC = 5.5 V

2.5

10

10

10

pF

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SN54AHCT240, SN74AHCT240

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