the proper pull up resistors value for MCU side and after PCA9511A

[tsi-chung_liew]

We have a I2C buffer 9511A populated on a arduino shield board, the I2C is coming from the EVK arduino header and to the buffer on arduino shield, the output of the I2C is 2.8V and to the camera module.

The current layout is the following:

what will be the proper setup?

Using this method?

Regards,

TC

[diazmarin09]

Hello TC,

I hope all is great with you. Thank you for using the NXP communities.

Your configuration seems correct to me. In any case, I would recommend testing your design.

C6=0.01uF is recommended .

Please let me know if I misunderstood your question.

I hope this information helps.

Regards,

David

[tsi-chung_liew]

David,

You have 45Kohm and 1Kohm highlighted. Is there a reason why it is needed 45K ohm? Or, 1K ohm? how is the 0.1 or 0.01 uF affect in the buffer or i2c signals?

[diazmarin09]

Hello,

Those are the maximum and minimum values for the pull-up resistor. Your design is within the range recommended.

In this case, the capacitor acts as a decoupler or filter for the power supply.

Regards,

David

[tsi-chung_liew]

how do user find out the right value instead of "within range" to use? i have 2.2K & 4.7K ohm with 0.01uF (going to try 4.7 & 4.7), this does not work. also, with 45k/45k with 0.1uF on three boards, only one work.