Nexperia

74LVC1T45; 74LVCH1T45

Dual supply translating transceiver; 3-state

13. Application information

13.1. Unidirectional logic level-shifting application

The circuit given in Fig. 15 is an example of the 74LVC1T45; 74LVCH1T45 being used in a

unidirectional logic level-shifting application.

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74LVC1T45

74LVCH1T45

VCC1

VCC2

VCC1

1

2

3

VCC(A)

GND

system-1

system-2

A

6

5

4

VCC(B)

DIR

B

VCC2

Fig. 15. Unidirectional logic level-shifting application

Table 16. Description unidirectional logic level-shifting application

Pin

Name

Function Description

1

VCC(A)

VCC1

supply voltage of system-1 (1.2 V to 5.5 V)

2

GND

GND

device GND

3

A

OUT

output level depends on VCC1 voltage

4

B

IN

input threshold value depends on VCC2 voltage

5

DIR

DIR

the GND (LOW level) determines B port to A port direction

6

VCC(B)

VCC2

supply voltage of system-2 (1.2 V to 5.5 V)

13.2. Bidirectional logic level-shifting application

Fig. 16 shows the 74LVC1T45; 74LVCH1T45 being used in a bidirectional logic level-shifting

application. Since the device does not have an output enable pin, the system designer should take

precautions to avoid bus contention between system-1 and system-2 when changing directions.

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74LVC1T45

74LVCH1T45

VCC1

VCC1

VCC2

VCC2

1

2

3

VCC(A)

GND

system-1

system-2

A

6

5

4

VCC(B)

DIR

B

I/O-1

I/O-2

PULL-UP/DOWN

DIR CTRL

PULL-UP/DOWN

Pull-up or pull-down only needed for 74LVC1T45.

Fig. 16. Bidirectional logic level-shifting application

74LVC_LVCH1T45

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Product data sheet

Rev. 9 — 10 February 2022

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