LTC4311 Wiring

I have a BME280 outside connected via ~50 of cat6 cable. The sensor did work but the humidity ranges were erratic. I figured it was the length of the cable and have been trying to get the LTC4311 connected and working. However, I am completely confused of how to wire it. I have tried simply connected it directly using the pins, and while it powers up, the BME280 does not work. I also tried jumping the EN pin to power. Lastly, I tried using the Stemma QT sockets, but that also did not work. I am running this 5v, not sure if that matters.

EN pin to power?
…running this 5V, With Esp32?

The BME280 can not run at 5V, It should be 3.3V (or lower, see Humidity Sensor BME280 | Bosch Sensortec). The LTC4311 should run at the same voltage as the BME280 and the I2C bus as well.
If you run the BME280 at 5V than this too high voltage might cause your issues. Running at 5V might maybe work for a short period of time, but it will fail after a much shorter period than expected.

Can you clarify if that’s mm or cm? Show your yaml as well if you can.

Feet or meters…?

Exactly. A few details would help. How even is the CAT6 connected up and the I2C frequency?

That did it! I changed to 3V and everything seems to be good now. I do have a question about the ‘EN’ pin. Should this be connected to 3V as well?


yes, EN should go to 3V as well

it should be internally pulled up.
You need to pull it low to disable.