I'm trying to use an I2C isolator IC (ADuM1251) to isolate one of the slaves on my I2C bus.
Without the isolator, the communication works fine. With the isolator, my setup is the following:
I'm using 1μF decoupling capacitors. The master is connected to side 1 and the slave to side 2. The pull-up resistors on each side are chosen so the rise time of the signal on each side falls within the I2C specification.
Using the isolator, a read from the slave will work for a few bytes and then stop working. From the scope it looks to me like the the slave can't drive the bus low.
This results in the master reading the first few bytes correctly and
0xFF for the remainder. The slave should be able to source enough current to drop the lines low (3.3V, 2.2kΩ, max current source per pin is 4mA).
Any advice on how to proceed is awesome!