PCA9548A i2c bus voltage support for 2.5V VDD

[rkanaman]

Hi,

For 8 channel I2C mux we would like to know if we could connect VDD to 2.5V and connect one of the downstream to 1.8V?

Configuration we are planning to use.

1. Upstream I2C bus-3.3V
2. 3 Downstream channels- 1.8V
3. 5 Downstream channels- 3.3V

From the AN262-2 Figure 7, it is not clear if 2.5V VDD can support 1.8V I2C bus

[guoweisun]

HI

 You can pull up downstream to 1.8V,no problem!

[rkanaman]

What is the maximum VDD supported for 1.8V I2C VBUS? With 2.5V VDD what will be the clamped voltage @ 1.8V side of the mux?

[guoweisun]

The typical maximum voltage of VDD should be around 2.8V@support 1.8V branch,the clamp voltage about typical 1.5V at 1.8V side under VDD 2.5V..