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TLA2024: About VDD and SCA/SCL supply voltage

Tsukui Yusuke
Guru 21930 points
Part Number: TLA2024
Other Parts Discussed in Thread: PCA9306

Hi,

Customers are trying to use the TLA2024 under the following conditions.
・VDD, AIN2 and AIN3₌5V
・SDA and SCL =3.3V

The VDD voltage is higher than the I2C pull-up voltage.
Is there a problem with this usage?




Regards,
Yusuke

  • 0
    TI__Guru* 93305 points

    Yusuke-san,


    Yes, this is a potential problem for operation. The logic input level for high received by the device is based on VDD. You can see it in the electrical characteristics table here:

    At 0.7*VDD, and with a VDD of 5V, this level is 3.5V, which is lower than the pull-up voltage of 3.3V. This means that a digital high may not be received by the TLA2024.

    Generally, I would use an I2C voltage level translator like a PCA9306 to go across different voltage levels. Also, it's possible that the master or other devices are tolerant to voltage levels higher than their supply, but you would need to check on those devices.


    Joseph Wu