What to look for in a H11L1?

[timmcross]

I see some of these are out of stock but there are stock in other variants. What factors should we look for in determining which part to get? Thanks!

Amazon:
https://www.amazon.com/SEMICONDUCTOR-Optocoupler-Channel-Digital-Output-6pack/dp/B095HK29NX/ref=sr_1_6?keywords=h11l1m+optocoupler&qid=1641670296&sprefix=h11l1%2Caps%2C93&sr=8-6

Digikey:
https://www.digikey.com/en/products/detail/H11L1M/H11L1MEL-ND/2691155?utm_campaign=buynow&utm_medium=aggregator&curr=usd&utm_source=octopart

[gmcn42]

Hi!

H11L1, H11L1M and even PC900V (Sharp) are basically the same part by different suppliers and can be used interchangeably in this circuit. See https://electronics.stackexchange.com/questions/306256/difference-between-h11l1-and-h11l1m for more info.

The reason to use H11L1(M) here is mostly because it is electrically compatible with the Raspberry Pi's 3.3V logic level. If at some point you'd want to substitute with a wholly different part, the value to look for in the datasheet is the Operating Voltage Range of the output (detector). The part needs to be fine with 3V.

Secondly, of course, pinout needs to be compatible and speed needs to be "at least as fast as MIDI", i.e. 31.25kbit/s. Not sure if there are actually any optocouplers slow enough for that to matter, though.

[gmcn42]

Oh and if you were asking if it makes any difference if the H11L1(M) comes from Everlight (H11L1MEL then I think?) or Fairchild/onsemi or whatever generic supplier might have them as well: It really shouldn't. If it does, then the supplier screwed up.