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ISO1640: ISO1640

Part Number: ISO1640

Dear Support,

Could you provide us the relation between the maximum value of the capacitor on SDA2 and SDCL2 lines and the data rate on them? (the same for SDA1 and SDCL1).

I think about the capacitor between lines and related GND (GND2 or GND1).

Have you got any document about acceptable filtering (capacitor, inductance, resistor, etc) we can add on those lines  related to the data rate?

Best regards.

Pierre Bruot

  • Hi Pierre,

    Thank you for posting, and welcome to E2E! Since the pull-up resistance on an I2C bus combines with the bus capacitance to create an RC delay on signal rise times, we normally calculate the maximum data rate a bus can support as a factor of the pull up resistance as well as the expected bus capacitance.

    Pull-up resistors are usually the easiest component to change on an I2C bus, so lower resistances can be used to support higher data rates and bus capacitances, as written in the I2C Bus Pullup Resistor Calculation (SLVA689) application report, liked here:

    Please refer to the steps and equations in the app report linked above, and let us know if you have any follow up questions.

    Manuel Chavez