I need to isolate the SPI communication between two chips.
The bottleneck of the communication is on the slave, which apparently can handle up to
2MHz SPI clock frequency.
My idea is to do this isolation using optocouplers. On this first attempt, I used the 4n35. It was just not working, so I looked on the datasheet and I saw the chip takes
10 us to rise and
10 us to lower the signal (on the worst case). This makes its use pointless.
Can someone suggest me an optocoupler that can:
- be fast enought for this purpose (2MHz, but 1MHz is also acceptable)
- be easy to buy and not expensive
I searched over the internet for an optocoupler that met those requirements, but I couldn't find one that was most recommendable.
I'm open to suggestions on how to isolate the communication in a different way, if it's practical.