TCA9544A: Host 3.3V + VCC 3.3V + 1.8V Slave

Ting Ye

Part Number: TCA9544A

Hello Team,

If I use TCA9544A with VCC 3.3V, host with 3.3V, and slave with 1.8V, will the I2C communication work?

Host 3.3V + TCA9544A VCC 3.3V + 1.8V Slave

My thought is due to TCA9544A VIH min VCC x 0.7 = 2.31V, the slave's VOH will not exceed 2.31V with 1.8V. So above configuration I2C communication will not work. Please share any comments.

Thank you.

Regards,

Ting

over 7 years ago

0 Lucas Schulte9 over 7 years ago

TI__Expert 6955 points

Ting,

You need to power this device with 3V or less in accordance with Figure 16 of the datasheet. This should allow your system logic levels to be translated appropriately.

-Lucas

0 Lucas Schulte9 over 7 years ago

TI__Expert 6955 points

Ting,

Also, refer to this e2e thread for more details on the subject.

e2e.ti.com/.../653447

-Lucas

0 Ting Ye over 7 years ago in reply to Lucas Schulte9

TI__Genius 11800 points

Hello Lucas,

Thank you for helping!
The TCA9544A VIH is confusing and the Vpass vs. Vcc graph is clear.

Regards,
Ting

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TCA9544A: Host 3.3V + VCC 3.3V + 1.8V Slave