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The application note on page 13 of the PCA9600 I2C extender/buffer datasheet shows pulldown capacitors C2 on the logic-level side of the I2C bus. I thought with I2C you want to minimize capacitance in the system to maintain sharp rises. What is the purpose of C2, and why does it increase with greater cable capacitance?

PCA 9600 i2c schematic

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1 Answer 1

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Those aren't actual caps you should put in. They represent the maximum capacitance of the bus wires between the PCA9600 and the master/slave.

If the cable capacitance is higher, the maximum clock speed is lower and that means those "C2 caps" may also be larger.

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