Part Number: TCA9548A
Hello, I have the following question regarding the use of pull-up resistors at the input of the multiplexer and also on the output to each channel. According to the datasheet, the switches have a low RON (18 ohms @ 3.3V, according to figure 5-4), therefore, for practical purposes, it can be considered a direct connection.
So I don't understand how it's possible to have pull-up resistors at both the input and output (figure 8-1), since we would be loading the SCL and SDA lines twice.
The datasheet -section 7.1- also mentions: "The TCA9548A may also be used for voltage translation, allowing the use of different bus voltages on each SCn/SDn pair such that 1.8-V, 2.5-V, or 3.3-V parts can communicate with 5-V parts. This is achieved by using external pull-up resistors to pull the bus up to the desired voltage for the controller and each target channel." But if the switches have Low Ron, as mentioned, then this would cause lines with a voltage of e.g. 3.3V to be connected (through the low value resistor of the switch) to a 5V line.
Thank you very much
