We are using ISOW7742FQDFMRQ1 in one of our designs with the following configuration:
VDD=3.3V, VIO=3.3V, VISO=3.3V. INB & IND grounded, OUTB & OUTD not connected. We are using 2 channels to provide isolated data at a rate < 1Mbps and other 2 channels are static. The isolated power supply provides 3.3V 60mA load.
For this configuration, how do we calculate max 3.3V supply current for this device?
Power converter (Section 7.10 of datasheet): VDD = 3.3 V, VSEL = GND2 ILOAD=60mA estimates max IDD=216mA
For VIO, VISOIN = 3.3V Section 7.14 of datasheet states max channel supply current - DC signal for VI=VCCI is 7.6mA for IDD_IO and 8.5mA for IISOIN. DC signal for VI=0 is 4.6mA for IDD_IO and 5.5mA for IISOIN.
I assume this is per channel, so if 2 channels have VI=VCCI and 2 channels have VI=0, supply current for DC signal is (7.6+8.5)*2 + (4.6+5.5)*2 = 52.4mA. Please confirm.
Since 2 channels are switching AC the supply current for 2 channels will need to include supply current for AC signal i.e. (6.3 + 7.2) = 13.5mA for all channels switching at 1Mbps. So I assume it will be half this for our case with only 2 channels switching i.e. 6.75mA. Please confirm.
Total current drawn from 3.3V supply will be summation of power converter + DC Signal + AC Signal i.e. 275mA. Please confirm.
Also, is the channel supply current IDD_IO (assumed to be per channel) drawn from VDD as well as VIO? If answer is yes... We have a separate configuration where VDD is 5V and VIO is 3.3V. How will the stated IDD_IO be split between the two supplies?