[Asmordo]

Good day!
I have a question or two about interfacing the Kflop, and I have not been able to find any other threads regarding this, even if there's lots regarding opto-couplers.
Since some I/Os have 150ohm pull-downs to make them 5V compatible, and other have 47ohm series resistors, I wondered if it's fine to connect the I/O's directly to an TI capacitive isolator ISO7240C chip that I'll be using only with 3.3V on the isolated side, or if I need something between them from case to case. Seems like it's standard to connect the ISO7240C inputs directly to the source outputs without pull-ups or downs and such, but it doesn't say anything in the manual, or how much the ic can take. I have not used this chip before so I would not want to damage the Kflop or such.
I would appreciate some advice on this.

Sincerely



Link to manual if interested:
http://www.ti.com/general/docs/lit/g...C&fileType=pdf

[TomKerekes]

Hi Asmordo,

It appears the outputs of the ISO7240C are only rated for 4ma which is insufficient to drive 150ohm loads. But you should be able to connect to any KFLOP pins without the 150ohm pull down resistors (those with 47 ohm series resistors or without).

HTH
Regards

[Asmordo]

Good day!
Thank you very much for you reply. That's partially good news. Is there any way to use the ISO7240C on the 150ohm pull down pins as well, without loosing to much speed? I have not used any of the 150ohm pull downs I/O as inputs for the ISO7240C, but if I would like to I would be glad for any options. I may have some IC in stock I could use even.
Sorry for the basic question, but I work mostly with Power Generation, so I have lot's of gaps when it comes to electronics. This is just for fun. =)

Sincerely

[TomKerekes]

Hi Asmordo,

Here is a post from yesterday regarding the same issue:
http://www.cnczone.com/forums/dynomo...ml#post1837404

HTH
Regards