Question
I want to know if it is possible to connect a I2C device to the Side 1 of your
ADuM1250 chip. The I2C device has SDA,SCL Input Logic-High (Vih) of 1.4 V
minimum, SDA,SCL Input Logic-Low (Vil) of 0.5 V maximum and SDA Output
Logic-Low (Vol) of 0.4 V maximum.
I know this iCoupler has an output logic low voltage of 0.9 V (max.) on Side 1.
For that reason I am not sure about its suitability to communicate with the
device desired in Side 1. Could you confirm if it is suitable or not?
Answer
The ADuM125x parts are not compatible with the Vil of your I2C device. Our part
typically drives its low output on side 1 at 0.85V, and a part that is rated
for Vil=0.5V will almost be guaranteed to have trouble reading our low level as
a low.
The side 1 output voltages are listed in the standard DC parameters spec table.
Side 2 of our device will be compatible with this voltage convention.