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TCA39306: VCCA & VCCB check

HSU HANWEN
Intellectual 290 points
Part Number: TCA39306


Hi

On the datasheet, it shows "Allows voltage-level translation between 0.9-V VREF1 and 1.8-V, 2.5-V, 3.3-V or 5-V VREF2" on description of "Feature".

But it also shows "To support translation, VREF1 supports 0.85 V to VREF2 - 0.6 V. VREF2 must be between VREF1 + 0.6 V to 5.5 V" under table of "6.3 Recommended Operating Conditions".

-

So I want to check :

(1)  If VREF1 = 0.85V, so VREF2(min) can be 0.85+0.6 = 1.45V?

(2)  My application will be VREF1(min) = 1.045V and VREF2(min) = 1.71V.

*VREF1(typ.) = 1.1V, VREF2(typ.) = 1.8V

=> Is this IC qualify for my circuit?

  • +1
    Guru 318760 points

    The values on page 1 are just examples.

    The only restriction is that the supply to which the resistor at VREF2 is connected should be at least 0.6 V higher than VREF1. So 1.1 V and 1.8 V is OK.

    (Please note that the pull-up resistors at the I/O pins can be connected to any voltage that is no lower than VREF1. So you could also use any higher voltage (e.g., 3.3 V) for the VREF2 circuit, if that happens to be available in your circuit.)

  • +1
    TI__Mastermind 45651 points

    Hey Hsu,

    Clemens is correct, your application (VREF1= 1.1V and VREF= 1.8V) will work with this device because it follows the requirement that VREF2 needs to be 0.6V greater than VREF1 for voltage translation. Note that the paragraph listed under "Features" just lists common voltage translation nodes that can be performed with the device. 

    Regards,

    Jack