TCA9617A: Can TCA9617A work for 1m 100ksps I2C communication?

Ruixin Feng

Intellectual 2735 points

Part Number: TCA9617A
Other Parts Discussed in Thread: TCA9617B, TCA9509

Tool/software:

Hi team,

I was wondering if customer need 1m distance I2C communication, can they use TCA9617A ? Thanks!
Rayna

over 1 year ago

0 Tyler Townsend over 1 year ago

TI__Guru 65368 points

Hi Ruixin,

I estimate about 1 pF / 1 cm of trace capacitance. Given this is a cable, the pF / cm might vary due to characteristics of the cabling.

1 meter of cabling adds inductance and ~ 100 pF of cap. I would recommend using a buffer such as TCA9617B (upgrade to TCA9617A).

What voltage levels is the customer working with?

What is the VIL of the target devices at the end of the cabling?

What kind of application is this for (end-equipment)?

Regards,

Tyler

0 Ruixin Feng over 1 year ago in reply to Tyler Townsend

TI__Intellectual 2735 points

Hi Tyler,

customer plan to use 2 device as serial connection to expand the I2C communication distance. #1: 3.3V to 5V. #2: 5V to 3.3V. the VIL of target device at the end of cabling is 0.3*3.3V. The application is ventilation machine.

Rayna

0 Tyler Townsend over 1 year ago in reply to Ruixin Feng

TI__Guru 65368 points

Hi Rayna,

Due to voltage recommended operating conditions, the lower supply exists on A-side (VCCA) while higher voltage exists on B-side (VCCB).

In this orientation, this means you have TCA9617B, B-side connected to another B-side of a series TCA9617B. This is not allowed. See this application note for more details on static voltage offset: https://www.ti.com/lit/an/scpa054/scpa054.pdf?ts=1719932118796&ref_url=https%253A%252F%252Fwww.google.com%252F

I would recommend using TCA9509 connecting to TCA9617B.

See this app note for the reasoning why we want to connect TCA9509 B-side to TCA9617B B-side.

https://www.ti.com/lit/an/slvafn4/slvafn4.pdf?ts=1720532530217&ref_url=https%253A%252F%252Fwww.google.com%252F

Regards,

TYler

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TCA9617A: Can TCA9617A work for 1m 100ksps I2C communication?