CTR of opto-coupler at low diode current (IF)?

[eem2am]

Hello,

Can i please confirm that even though the CNY17-2 opto-coupler has a stated CTR of 63% to 125%, .....this does not apply at all levels of diode current?

For example ,Figure 5, page 5 appears to show that the CTR of CNY17-2 is just 30% at a diode current (IF) of 500uA ?

So do you agree that at low diode currents, the stated "63% to 125%" CTR is meaningless?


CNY17-2 DATASHEET:
https://www.vishay.com/docs/83606/cny17.pdf

 

[dick_freebird]

I don't disagree or disagree specifically, but every BJT has a
rolloff of hFE at low current and every LED has an output
efficiency curve that peaks as well.

I expect if you read the fine print, that CTR is spec'd over a
range that makes them look good, not necessarily the range
where you would like to use it.