I2C: Maximum I2C Bus Length

Oscar Gomez Fuente

Expert 2066 points

Hi everyone,

I would like to know what the maximum length for the I2C bus can be used.

I need to use a the I2C bus of a MSP430 microcontroller, to connect with 3 temperature sensor. The problem is that theses 3 temperature sensors are separated 1 meter from each other. This is the schematic:

Best regards.

over 3 years ago

0 Josh Wyatt over 3 years ago

TI__Guru* 91206 points

Dear Oscar -

Thanks for posting! The I2C spec has specific guidance for length and conductor order for application usages over 10cm in section 7.5 (see page 60 of the attached) as well as guidance on minimizing bus capacitance, proper pullup resistor sizing and usage of (multiple other places in the document, most notably in that same section 7, which starts on page 55)

/cfs-file/__key/communityserver-discussions-components-files/1023/5327.I2C-Spec_5F00_UM10204.pdf

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I2C: Maximum I2C Bus Length