ISO7820LL: isolation between graphic processor and TFT LCD

Hello Seo, 

Thank you for reaching out. I am assuming the RGB signals you mention are CMOS, logic-level signals, based on your description. If the RGB signals are logic level signals, then you could use either a digital isolator (ISO7730) or an I2C isolator (ISO1640) to isolate these signals. The I2C isolator would be recommended if the signals are going to an external PCB over a short distance of wire.

You would not need to use a differential protocol for these signals (like LVDS) unless the signal needed to travel longer cable lengths. 

Best,
Andrew 

Hello Seo, 

There will be no issues in transmitting signals across 8 IC's as long as all the devices are powered. Please note that data sheet specifications are characterized across process, voltage and temperature (unless otherwise noted in the table). This means the datasheet specs account for part-to-part variation. 

In general, it is up to the MCU to handle the protocol and timing of the communication. 

Best,
Andrew

Yes, your understanding is correct. You can also use a higher channel count isolator to save some board space, like ISO7760. 

Best,
Andrew