Somehow, this component is dragging my entire 3.3V bus up to 5V. Hereâs the setup:
Iâm only using one TX channel. The high side is 5V, and the low side is 3.3V. I bring the reset pin from an Arduino into the TXO channel on the high side (it should be held at 5V except to reset). I havenât yet connected the TXI on the low side to anything. When I power on, my 3.3V bus is brought up to 5V! Iâve tested for a short; there is none. If I remove the component, my 3.3V bus is in fact 3.3V. Further, if I tie the TXI on the low side to ground via a 1kOhm resistor, I find that my 3.3V bus returns to 3.3V. Iâve also tested all of my connections; theyâre good.
Does anyone have any idea whatâs going on? Leakage current? Directionality?