TCA9543A: TCA9543A

Sathya Priya

Part Number: TCA9543A

Dear Team,

We are using this TCA9543 I2C mux in our design.

Whether we need to provide the external pull up resistor for I2C lines (SDA & SCL) on the output side of slave channel 1 and 2.

Or pull up resistor is incorporated internally for I2C lines? It is sufficient for IC to work properly?.

Thanks,

Sathya.

over 2 years ago

0 BOBBY over 2 years ago

TI__Guru* 78111 points

Hi Sathya,

An external pull up resistor on the secondary channels of the device is required if you do not have internal ones from the devices on that side.

Essentially pins SDA/SCL, SD0/SC0, and SD1,SC1 all require pull up resistors.

-Bobby

0 Sathya Priya over 2 years ago in reply to BOBBY

Intellectual 270 points

Hi Bobby,

Thanks for you reply.

So you are confirming that I2C MUX is not having any internal pullu right?

I will add External pull up resistor for input side and output side of I2c mux.

Correct if i am wrong.

0 BOBBY over 2 years ago in reply to Sathya Priya

TI__Guru* 78111 points

Hi Sathya,

Correct, there are no internal pull up resistors in TCA9543. If you use it without pull up resistors your voltage will probably float to Vcc-1V on the secondary channels.

-Bobby

+1 Clemens Ladisch over 2 years ago in reply to Sathya Priya

Guru 320410 points

This mux allows level shifting by connecting the external pull-up resistors to voltages higher than V_CC. With internal pull-up resistors, this would not be possible.

0 Sathya Priya over 2 years ago in reply to BOBBY

Intellectual 270 points

Thank you so much.

0 Sathya Priya over 2 years ago in reply to Clemens Ladisch

Intellectual 270 points

Ok thanks for the inputs

0 Sathya Priya over 2 years ago in reply to Sathya Priya

Intellectual 270 points

Hello Team,

While validating CCI I2C lines in mux IC any thing should be taken care from software end?

0 BOBBY over 2 years ago in reply to Sathya Priya

TI__Guru* 78111 points

I'm not familiar with the term CCI, what specifically are you trying to validate?

From a software perspective, I recommend always performing a stop condition after writing to the TCA9543A to ensure the channels you enable/disable are executed. The device does not execute the write if you perform a repeated start condition on the bus, it waits for a stop condition to perform the enable/disable command.

-Bobby

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TCA9543A: TCA9543A