Re: question for Mariss

Jon,

I'm familiar with the part. What you have here is specmanship; the
2uS on/off times are for non-saturated operation into a 100 ohm load.
The results are a little more depressing for saturated operation:

1K load, 3uS on, 15uS off (55kHz max)
10K load, 3uS on, 170uS off (5.8kHz max)

We use the HCPL-2531 opto which is a photo-diode type. A 10K load
yields 300nS on time and 2.7uS off time for a typical max freq of
around 330kHz which we derate to a specified 200kHz.

Mariss

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:
>
>

> Well, I think there are some that are fast. Check the Fairchild
H11AA3
> and H11AA4
> (page 1019 in the Digi-Key catalog). They claim 2 uS on and off
times.
> The 100 uS
> ones usually have Darlington transistor outputs, which is what
slows
> them down.
>
> There were some LiteOn ones on the next page or so that were spec'd
at
> 4/3 uS, but
> they were more expensive, too.
>
> Jon