I need to connect to MCU´s togther through an opto-coupler. Basically one sends pulses to the other, speed is not important as it will be worse case a couple of pulses per second, but generally much less than that.
I will be using a Vishay VO615A-8X017T part, datasheet here if needed.
http://www.vishay.com/docs/81753/vo615a.pdfBasically the configuration is simple, MCU > Resistor > Anode - Cathode > GND on the input side and the
collector emitter tied to ground, with the
emitter collector going to the other MCU with a 10K pull-up resistor. The reason for 10K is that I already have a few 10K resistors on the board doing other things, so I need less values on the board. Is that OK to do?
So if I have understood everything correct, then there is 500uA on the collector (5v through 10K), so I need to supply at least that amount to the LED to get the Transistor to switch on fully. From the datasheet, the CTR is 130 - 260% so if i give the LED the same, 500uA, there should be plenty to switch the transistor on. The LED side is 3.3V, and the LED Vf is 1,05 at 500uA, so I would need 4,5k (4,7K is a better value) resistor.
Is that right?
Thanks.