When you don't have the part you want to use, make it. ;-)
I wanted to separate my SI/OP control and R 2R circuits, with a
photo-diode and LED, I'm able.
The photo-diode is made for fiber-optic cable, so I had to drill it
out a little, for the LED to fit.
The circuit is rather simple and effective. Add R1-R2, your source
and Q1 to handle the load.
