TCA39306-Q1: TCA39306-Q1 as a UART Switch / Buffer

Anirudha Ram

Part Number: TCA39306-Q1
Other Parts Discussed in Thread: SN74LVC2G66, SN74LVC2G125-Q1, TCA9517-Q1, SN74LVC1G126-Q1

Hello,

How to use the TCA39306-Q1 device as a UART switch (also as a kind of buffer)? I understand that the TCA39306-Q1 is typically used for voltage level translation for the I2C/I3C bus, but I am specifically interested in how to implement it in a UART communication setup to effectively switch and buffer the signal line.

Please provide guidance on how to configure the TCA39306-Q1 for this use case? Additionally, I would greatly appreciate it if you could share or point me to an application schematic showing the correct connections for using the TCA39306-Q1 as a UART switch/buffer.

Thank you.

8 months ago

+1 Clemens Ladisch 8 months ago

Guru 317390 points

This device is a passive switch; it cannot be used as a buffer.

To disconnect both sides, pull EN low. (Because of the biasing circuit, this must be done with an open-collector or open-drain driver.)

The easiest way to switch to signal lines would be an actual switch like the SN74LVC2G66. To buffer two lines, use a buffer like the SN74LVC2G125-Q1 (its /OE inputs are active low).

0 Anirudha Ram 8 months ago in reply to Clemens Ladisch

Prodigy 90 points

I was wondering if I can use the TCA9517-Q1 as a UART buffer?

+1 Clemens Ladisch 8 months ago in reply to Anirudha Ram

Guru 317390 points

The TCA9517-Q1 is an I²C buffer and is designed for bidirectional open-drain signals. It would work, but the SN74LVC2G125-Q1 is cheaper and more robust in this application. If you need an active-high enable signal, use 2× SN74LVC1G126-Q1.

0 Tyler Townsend 8 months ago in reply to Anirudha Ram

TI__Mastermind 48338 points

Anirudha,

Please let me know if you have any more questions.

Regards,

Tyler

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TCA39306-Q1: TCA39306-Q1 as a UART Switch / Buffer