Hello everyone,
I'm working on a design using an nRF SoC and have a question about the correct way to handle I2C pull-up resistors in a mixed-voltage system.
My Setup:
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The main part of my board, including the nRF (which is the I2C master), is powered at 3.3V.
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I have a separate, isolated analog section on the board to avoid noise. This section includes a sensor IC that is powered at 3.0V.
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The I2C bus (SDA/SCL lines) needs to connect the 3.3V nRF to this 3.0V sensor.
My Question: Both the nRF and the sensor are connected to the same I2C bus, which requires pull-up resistors. I'm unsure what the correct voltage is for these pull-ups.
Should the I2C pull-up resistors be connected to the main 3.3V rail or to the analog section's 3.0V rail? What is the standard best practice for this scenario to ensure safe and reliable communication without damaging either component?
Thanks for your help, Oriol
