TCA39306: Topology

Lenex Guo

Part Number: TCA39306

Here are two questions about the topology,

1. Is the topology acceptable with SCL1/SDA1 connected to the Device and SCL2/SDA2 connected to the Controller?

2. connecting multiple TCA39306s in series with SCL2/SDA2 side connecting to SCL2/SDA2.

Screenshot 2026-09-02 123154.png

Thank you,
Lenex

1 month ago

0 Tyler Townsend 1 month ago

TI__Guru 66018 points

Hi Lenex,

Are you trying to maintain I3C SDR at 12.5 MHz for this application or can you use I3C at reduced clock rate?

Regards,

Tyler

0 Lenex Guo 1 month ago

Prodigy 10 points

Hi Tyler,

Our board has two buses with this topology, Both I3C buses operate at 12.5 MHz, but one of them can be configured as I2C only.

Regards,
Lenex

0 Brian Lin (TXP) 1 month ago in reply to Lenex Guo

TI__Intellectual 1735 points

Hi Lenex,

Tyler is on sick leave today. He will respond it to you shortly once he is back.

Thanks

Brian

0 Tyler Townsend 1 month ago in reply to Lenex Guo

TI__Guru 66018 points

Hi Lenex,

I2C would work here.

I3C might be more difficult as daisy chaining two TCA39306 adds input cap. There is also trace cap. Since TCA39306 is a passive level shifter, the output rising waveform relies on a pull-up resistor when translating up. 1.0V to 1.8V would be a difficult application to achieve with push-pull re-driving at 12.5 MHz.

I think you would need some type of buffering device here or a I3C application at reduced clock rate.

Regards,

Tyler

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TCA39306: Topology