Yet again I'm working with the sub-set parts the PCB assembler house has pre-loaded, and not what is commercially available. Like using 3-6 resistors in place of 1, and more relevant to this question; series-ing capacitors with balance resistors to raise the maximum voltage specification.
Can you do this with optocouplers in a series stack, with or without balance resistors?
My example is two Everlight EL357 which is a 80V part. It costs about 5½¢ (0.055USD) and is pre-loaded at my assembler.
My use is in a system where the over-volt protection begins at 90V, so for parts that are externally exposed, I want 120V limits or higher (150V being common.)
I could buy Renesas PS2913-1-V-F3-AX which is a 120V part, but it costs $2.23, then add shipping, add storage cost at the assembler, and a per-job load-fee for non pre-loaded parts. This will easily get the part to the $5 range for small order jobs (20-30 boards.)
There are also other types of optocouplers, but my board house only has 4 preloaded and they are all the transistor output type, so the same problem as a Renesas if I were to switch types.
So $5.00 or $0.11? This is why I ask these questions.
