Contact us

A new window will open A new window will open

Is it necessary to add an external pullup resistor between the input or output pin of a level-shifting bus switch and the power supply (VCCA or VCCB)?

The input side does not need a pullup resistor whereas the output side must be pulled up to the supply voltage.

When a bus switch is used bidirectionally as shown in Figure 1, both A and B can act as an output. Therefore, both these pins require a pullup resistor.

When a bus switch is used unidirectionally as shown in Figure 2, the input pin (A) does not need a pullup resistor whereas the output pin (B) must be pulled up to VCCB.

Figure1 Bidirectional level-shifting

Figure1 Bidirectional level-shifting

Figure2 Unidirectional level-shifting

Figure2 Unidirectional level-shifting

To Top
·Before creating and producing designs and using, customers must also refer to and comply with the latest versions of all relevant TOSHIBA information and the instructions for the application that Product will be used with or for.