TCA9548A: Cascade with TCA9517A

TI-CSC

Genius 13640 points

Part Number: TCA9548A
Other Parts Discussed in Thread: TCA9517, TCA9517A, TCA9509

Tool/software:

Hello E2E Experts,

Good day.

Will the configuration below work?

If not, , what compatible level shifter device can replace the TCA9517?

Regards,

TICSC

2 months ago

0 Katy West 2 months ago

TI__Expert 4445 points

Reassigning to the TXP team who can advise on if TCA9517 is good/ if a replacement is needed!

0 Tyler Townsend 2 months ago

TI__Guru 50108 points

TICSC,

This implementation will not work.

The B-side of TCA9517A faces B-side of TCA9517A. The TCA9548 I2C switch is a passive device meaning that only a small resistance connects both TCA9517A buffer devices through a passFET.

The VILC spec of the TCA9517A will be violated due to the VOLB spec of the buffer. Recommendation is to switch one of the TCA9517A's with the TCA9509 and adjust the design accordingly. See this application note. https://www.ti.com/lit/an/slvafn4/slvafn4.pdf?ts=1720532530217&ref_url=https%253A%252F%252Fwww.google.com%252F

Another solution would be to switch A and B sides of one of the TCA9517A buffers. Allowed connections are A-A, A-B, B-A, but never B-B.

Regards,

Tyler

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TCA9548A: Cascade with TCA9517A