[sdiy] MIDI optocouplers

[Fredrik Carlqvist]

Nice unit! 

But the opto-coupler uses a 220 Ohm resistor, which is even worse for my
application. Aren't there any opto-couplers that can handle the 2us
rise/fall time with a 10k resistor?


Fredrik C

-----Original Message-----
From: carsten at analog-monster.de [mailto:carsten at analog-monster.de] 
Sent: Friday, November 12, 2004 11:52
To: Fredrik Carlqvist
Cc: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] MIDI optocouplers


Hi Fredrik,

I use the PC900 optocoupler. Schematic on

http://www.analog-monster.de/ucvm_en.html

-Carsten

Fredrik Carlqvist <ifrc at iar.se> schrieb am 12.11.2004, 10:15:24:
> 
> Hi All!
> 
> I've tried several optocouplers for MIDI IN, but lately I use SFH620 (and
> TLP620). Since they are AC couplers, I solder the MIDI connector right
100%
> of the time (instead of just 20%). However, they need a very small
> resistance (470 Ohm on a 5V system) on the collector or the rise time is
too
> slow. And that introduces switching noise.
> 
> What optocouplers do you use for MIDI?
> 
> 
> Fredrik C
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