SN54/74LS242 SN54/74LS243

QUAD BUS TRANSCEIVER The SN54 / 74LS242 and SN54 / 74LS243 are Quad Bus Transmitters / Receivers designed for 4-line asynchronous 2-way data communications between data buses.

• Hysteresis at Inputs to Improve Noise Immunity • 2-Way Asynchronous Data Bus Communication • Input Clamp Diodes Limit High-Speed Termination Effects

QUAD BUS TRANSCEIVER LOW POWER SCHOTTKY

LOGIC AND CONNECTION DIAGRAMS DIP (TOP VIEW) SN54 / 74LS242 VCC

GBA

NC

1B

2B

3B

4B

14

13

12

11

10

9

8

J SUFFIX CERAMIC CASE 632-08 14 1

1

2

3

4

5

6

7

GBA

NC

1A

2A

3A

4A

GND

SN54 / 74LS243 VCC

GBA

NC

1B

2B

3B

4B

14

13

12

11

10

9

8

N SUFFIX PLASTIC CASE 646-06

14 NOTE: The Flatpak version has the same pinouts (Connection Diagram) as the Dual In-Line Package.

1

D SUFFIX SOIC CASE 751A-02

14 1

ORDERING INFORMATION 1

2

3

4

5

6

7

GBA

NC

1A

2A

3A

4A

GND

SN54LSXXXJ Ceramic SN74LSXXXN Plastic SN74LSXXXDW SOIC

TRUTH TABLES SN54/74LS243

SN54 / 74LS242 INPUTS

INPUTS OUTPUT

GAB

D

L L H

L H X

H L (Z)

INPUTS OUTPUT

GAB

D

L H H

X L H

INPUTS OUTPUT

(Z) H L

GAB

D

L L H

L H X

H = HIGH Voltage Level L = LOW Voltage Level X = Immaterial Z = HIGH Impedance

FAST AND LS TTL DATA 5-1

L H (Z)

OUTPUT GAB

D

L H H

X L H

(Z) H L

SN54/74LS242 • SN54/74LS243 GUARANTEED OPERATING RANGES Symbol

Parameter

Min

Typ

Max

Unit

VCC

Supply Voltage

54 74

4.5 4.75

5.0 5.0

5.5 5.25

V

TA

Operating Ambient Temperature Range

54 74

– 55 0

25 25

125 70

°C

IOH

Output Current — High

54, 74

– 3.0

mA

54 74

– 12 – 15

mA

54 74

12 24

mA

IOL

Output Current — Low

DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified) Limits S b l Symbol

Min

P Parameter

VIH

Input HIGH Voltage

VIL

Input LOW Voltage

VT+–VT–

Hysteresis

VIK

Input Clamp Diode Voltage

VOH

Output HIGH Voltage

VOL

Output LOW Voltage

IOZH IOZL

IIH

Max

U i Unit

2.0 54

0.7

74

0.8 0.2

0.4 – 0.65

54, 74

2.4

54, 74

2.0

– 1.5

3.4

T Test C Conditions di i

V

Guaranteed Input HIGH Voltage for All Inputs

V

Guaranteed Input p LOW Voltage g for All Inputs

V

VCC = MIN

V

VCC = MIN, IIN = – 18 mA

V

VCC = MIN, IOH = – 3.0 mA

V

VCC = MIN, IOH = MAX VCC = VCC MIN, VIN = VIL or VIH per Truth Table

54, 74

0.25

0.4

V

IOL = 12 mA

74

0.35

0.5

V

IOL = 24 mA

Output Off Current HIGH

40

µA

VCC = MAX, VOUT = 2.7 V

Output Off Current LOW

– 200

µA

VCC = MAX, VOUT = 0.4 V

D, E1, E2

20

µA

VCC = MAX, VIN = 2.7 V

E1, E2

0.1

mA

VCC = MAX, VIN = 7.0 V

D Input

0.1

mA

VCC = MAX, VIN = 5.5 V

– 0.2

mA

VCC = MAX, VIN = 0.4 V

– 225

mA

VCC = MAX

mA A

VCC = MAX

I HIGH C Input Current

IIL

Input LOW Current

IOS

Output Short Circuit Current (Note 1)

ICC

Typ

– 40

Power Supply Current Total, Output HIGH

38

Total, Output LOW

50 LS242

50

LS243

54

Total at HIGH Z Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.

FAST AND LS TTL DATA 5-2

SN54/74LS242 • SN54/74LS243

AC CHARACTERISTICS (TA = 25°C, VCC = 5.0 V) Limits LS242 Symbol S b l

Parameter P

Min

LS243

Typ

Max

Min

Typ

Max

Unit U i

tPLH tPHL

Propagation Delay, Data to Output

9.0 12

14 18

12 12

18 18

ns

tPZH

Output Enable Time to HIGH Level

15

23

15

23

ns

tPZL

Output Enable Time to LOW Level

20

30

20

30

ns

tPLZ

Output Disable Time from LOW Level

15

25

15

25

ns

tPHZ

Output Disable Time from HIGH Level

10

18

10

18

ns

Test C Conditions di i T

CL = 45 pF, RL = 667 Ω

CL = 5.0 p pF,, RL = 667 Ω

AC WAVEFORMS

VIN

1.3 V tPLH

VOUT

VCC

1.3 V tPHL

1.3 V

RL

1.3 V SW1

Figure 1 TO OUTPUT UNDER TEST VIN

1.3 V

1.3 V tPHL 1.3 V

VOUT

5 kΩ

tPLH CL*

1.3 V

SW2

Figure 2

VE

1.3 V

VE

1.3 V tPZL 1.3 V

VOUT

SWITCH POSITIONS

tPLZ

0.5 V

≈ 1.3 V VOL

Figure 3

SYMBOL

SW1

SW2

tPZH

Open

Closed

tPZL

Closed

Open

tPLZ

Closed

Closed

tPHZ

Closed

Closed

VE 1.3 V VE

1.3 V

tPZH VOUT

1.3 V

Figure 5 tPHZ ≥VOH ≈ 1.3 V 0.5 V

Figure 4

FAST AND LS TTL DATA 5-3