TCA39306: using for I2C level shifting and switching

Kentaro.Kori

Prodigy 15 points

Part Number: TCA39306
Other Parts Discussed in Thread: SN74LVC2G66, LSF0002

Tool/software:

Hi,Teams

I am considering using TCA39306 for I2C level shifting and switching.

The pull-up voltage can be adjusted to 1.2V/1.8V/3.3V, but it should be set so that V_PU1≦V_PU2.

I believe that the attached circuit should work fine if there is a voltage difference.

Would it also work if V_PU1=V_PU2?

3 months ago

+1 Julius Burtell 3 months ago

TI__Prodigy 667 points

Hello,

Yes, V_PU1 can equal V_PU2.

Best,

Julius Burtell

+1 Clemens Ladisch 3 months ago

Guru 267980 points

This will work, but if you actually know that a specific circuit has the same voltages, then there are simpler and cheaper switches, e.g., SN74LVC2G66.

The TCA39306 is designed to allow high-frequency applications. For most I²C applications, the simpler and cheaper LSF0002 wold suffice.

Please note that two 470 Ω pull-ups in parallel result in too much pull-up current.

0 Kentaro.Kori 3 months ago

Prodigy 15 points

Thank you for your response.

I feel relieved to know that the circuit is functioning.

I will reconsider the pull-up resistor.

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TCA39306: using for I2C level shifting and switching