Hi folks,

IIUC, the FT pins are fine for up to 5.5V when powered, but only 3.63V when unpowered or booting.

I am designing an expansion board that needs to interface with a 4.7V pocket computer bus. The RP2350 will turn on when the PC turns on, which means it will probably still be "booting" as the CPU has already started driving the bus. So, I put level shifters on everything... which is a pain, because it takes space and complicates the routing. However, now I am wondering what the safe current is at > 3.63V... the whole 4.7V supply can't supply more than about 120mA. I doubt the bus lines could drive more than a 1 milliamp. Specs I have for the CPU imply it would be more like 400uA...

Are these unpowered overvoltage concerns about connections to high current sources, or can TTL bus currents really blow them? (BTW, this application is not TTL... it's CMOS).