TLP114 Faraday shielded Optocoupler alternative ?

[BGAmodz]

Hello everyone here , and happy Christmas .

Am wandering if i could use a normal phototransistor like a PC817 or 814 as a replacement for this one " TLP114 faraday shielded phototransistor " .

I don't know why this shield is used on it ??

 

[MikeMl]

Ultra high isolation (for capacitive coupling). If you don't need that, then any standard opto-coupler will work.

 

[BGAmodz]

Thanks mikeml
I have replaced the faulty one on my card with normal phototransistor , but i get the same behavior as with the faulty .
I possess a card that controls a 12 v 8 amps soldering unit , it got 7 seg display to display the soldering settings that are controlled with a panel , the problem i get is when i power up the unit , the display starts and then shuts down , normaly it should display the current soldering settings as long as the unit is on .

 

[BGAmodz]

Maybe best is to get the proper replacement

 

[rumpfy]

The TLP114 is a higher gain device and it appears to be faster. The rise time for the TLP is 0.8 microsecond and the PC is 4 to 18.
It looks like you will need the TLP

 

[BGAmodz]

Back on topic again .

So after inspecting the card to see if something is wrong , i have checked an Optocoupler , checked the diode pins using diode mode and i didn't see any reading , so i assumed that the optocoupler's diode is dead .

Now after ordering brand new optocouplers , i found the same thing on them .

Is it possible that the optocoupler is normally like that ?
BTW the IC is TLP 114 .

 

[rumpfy]

If you are referring to the LED part of the coupler, the data sheet says Vf is 1.5 +/- a bit. Are you testing this with an ohm-meter type of tester with a 1.5 volt battery on the ohms range. If so that might be the problem. The diode runs at about 15 to 20 mA at the forward voltage of 1.5V. Use a 3 volt supply in series with say 100 ohm resistor. Should get at least 8 to 10 mA in the LED
The only way you get the output transistor to conduct is by illuminating the led.
Does this help.

 

[BGAmodz]

Hi

Unfortunatly even after doing a test circuit , using a 12 v and a 470 ohm resistor in series with the led , nothing works , there is no saturation of the transistor .

I think i have received bad parts .

 

[rumpfy]

The absolute maximum forward current is stated to be 20 mA. I hope you haven't stuffed it with too much forward current. The 12 volt/470 ohm setup gives me 22.3 mA
I note too on the data sheet there is confusion on page 1.
Pin 1 is shown on the schematic as the anode
Pin 1 is shown on the 'pin configuration drawing' as the cathode; but the list of pin connections says pin 1 is anode.
Just check the information you are using.
Note that the maximum reverse voltage is 5 volt. So I would NOT use more than 5 volt to check this led. You should be looking for a forward current to establish if the led is ok. Then check the receiver. Page 4 test circuit 1 is how to connect the receiving diode.