Hello,
I have a question about a solid state relay. The IXYS Form C, LCC110. My question is about the polarity on the output. The control side is clear but not the switched side. Im wondering if the polarity matters on the pins 5,6,7,8.

Datasheet Link: https://www.mouser.com/datasheet/2/240/lcc110-1546141.pdf

Thanks

 

Hello,
I have a question about a solid state relay. The IXYS Form C, LCC110. My question is about the polarity on the output. The control side is clear but not the switched side. Im wondering if the polarity matters on the pins 5,6,7,8.

Datasheet Link: https://www.mouser.com/datasheet/2/240/lcc110-1546141.pdf

Thanks

No, the polarity does not matter except for the input/LED drive. However, there are other caveats hidden in the datasheet. If current flows through both of the outputs simultaneously, then the device power rating must be considered since both outputs then generate internal heat; I don't understand how that is possible in a Form-C device.

 

Yeah, considering one or the other would be open.

 

It doesn't switch instantaneously. The turn-on time might be faster than turn-off by a good fraction of a ms causing an overlap. That might be a factor in high frequency switching applications.

 

Ah, I see. I don't think that will be a factor in my application. I'm literally using a physical switch for control. I didn't want nor need a coil relay. Much thanks for your help.

 

Ah, I see. I don't think that will be a factor in my application. I'm literally using a physical switch for control. I didn't want nor need a coil relay. Much thanks for your help.

Just remember that physical switches have contact bounce. You might be toggling the SSR several times before the contacts settle.
https://www.allaboutcircuits.com/technical-articles/switch-bounce-how-to-deal-with-it/

 

Ok I see. In the example I would be using the high side switch w the R/C components. Being a novice, wouldn't the cap charge and then trigger without the switch being thrown? If I wanted to switch 12v positive, could I use the same setup as in the example and get the same clean result?

 

It doesn't switch instantaneously. The turn-on time might be faster than turn-off by a good fraction of a ms causing an overlap. That might be a factor in high frequency switching applications.

@nsaspook
You are correct; the Ton, Toff times are spec'd at 4ms max. However, if the switch is connected as SPDT with the selector contact switching alternately from a +V to a -V source (as in PWM), then the momentary short from +V to -V might considerably increase dissipation as well as cause current spikes at the +V & -V supplies. I believe that using the device in such manner would be rare, but the effect is certainly worth noting.