Electronic – Analog Mux as Cheap I2C Mux


Just looking to have two devices on a single bus with the same address. There are many I2C multiplexers available, but they seem to cost ~4x what a 2x 2:1 analog multiplexer costs.

Any reason I can't use an analog multiplexer for I2C running a 100kHz bus?

For example a TI TS3A5223RSWR is 0.63 cents, and based on the data sheet, supports bi-directional analog signals with a small ~1 Ohm impedance.

Best Answer

Analog multiplexers work just fine for I²C signals (if you keep the impedance and parasitic cpacitance small enough, which is usually not a problem).

I²C multiplexers are more complex because they are controlled through the I²C bus itself. You need one if you do not have a spare GPIO pin to control it.