TCA9539-Q1: Is the IO level following VCC?

xiwen Yan

Part Number: TCA9539-Q1
Other Parts Discussed in Thread: TCAL6416, TCA6416A

Tool/software:

Is the IO level following VCC, or is it allowed as long as the voltage is less than VCC? If VCC is 3.3V, is the IO level allowed for both 1.8V and 3.3V, or can it only be 3.3V

7 months ago

+1 Clemens Ladisch 7 months ago

Guru 316690 points

Voltages between V_IL and V_IH are not allowed. So you must use 3.3 V signals.

0 Tyler Townsend 7 months ago

TI__Mastermind 47328 points

Hi Xiwen,

IO levels follow VCC according to your explanation.

If you need separate logic levels for the I2C and GPIO level side, then consider the TCA6416A or TCAL6416.

Given you are looking at an automotive part, we do not have TCAL6416 or TCA6416A in Q1.

However, we do have TCA6408A-Q1, but this is a 8-bit I2C IO expander and not a 16-bit.

Regards,

Tyler

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TCA9539-Q1: Is the IO level following VCC?