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PCAL6408A voltage design

Question asked by Morgan Jiang on Jan 7, 2020
Latest reply on Jan 8, 2020 by Tomas Vaverka

As mentioned in the PCAL6408A  datasheet:


There are two supply voltages for PCAL6408A: VDD(I2C-bus) and VDD(P).

VDD(I2C-bus) provides the supply voltage for the interface at the master side (for example, a microcontroller) and the VDD(P) provides the supply for core circuits and Port P.

The bidirectional voltage level translation in the PCAL6408A is provided through VDD(I2C-bus).

VDD(I2C-bus) should be connected to the VDD of the external SCL/SDA lines.

This indicates the VDD level of the I2C-bus to the PCAL6408A, while the voltage level on Port P of the PCAL6408A is determined by the VDD(P).



In Our design, VDD(I2C-bus) and the high-level voltage of Port P are equal (both 3.3V), can VDD(I2C-bus) and VDD(P)  can be connected together?