Which datasheet CTR value to use in optocoupler circuit?
First, can your IC withstand ~12V on the input? I ask because those are TTL levels and its rare to have a chip that has that capability (outside of LDOs and similar special purpose devices).
The &quot;saturated CTR&quot; is the ratio of the specified output current to the current through the LED required to lower Vce to 400mV. At least that would be my assumption. So for the B bin you would need 1mA/.45 or 2.2mA. The unsaturated CTR is applicable in this case since you don't need Vce to drop to 400mV.
You should also account for temperature extremes and for aging, which might be another 2:1 or 3:1 depending on the LED quality and what temperatures you need to account for.
Your 8uA maximum dark current is also rather optimistic, 40uA or 50uA might be a safer number to use for Vce = 11.6V.