A little background on my setup. The ICM-20689 is running on 3.3V with 3.3V on the VDDIO pin and 10k pullup resistors on the I2C bus. The master device is running at 5V, but only needs 60% (3V) to read a voltage high. The frequency is set to 400kHz.
I have been able to communicate with the device just fine and get good data. I wanted to look at the bus voltages with an oscilloscope to make sure that everything looked fine, and I noticed something a little odd. Before the master starts talking with the ICM-20689, the bus line is at a voltage of 3.3V. When the master wakes up the device and starts receiving data, the voltage jumps to 3.7V.
My oscilloscope is not the greatest, but the probe is in 10x mode, and I am using the trigger to capture the data on the first packet of data sent. On all subsequent data packages, the voltage stays at 3.7V. Is this is an issue with the device, or is this maybe an issue with my measurement setup?
Edit: Here is the schematic for the ICM-20689. This "voltage bump" happens on both the SCL and SDA lines. To my knowledge, there are no internal pull-ups active on any devices on the bus.
Is this normal for I2C? What is causing this bump? Is this something I should be worried about, or is this within allowable tolerances?