I'm looking for a circuit/IC to shift logic levels between 1.8/3.3/5V and 3.3V.
This is to connect various devices via UART to the ESP8266. As such, I only need unidirectional translation - the ESP8266 TXD operates at 3.3V and should be shifted to 1.8/3.3/5V according to a reference voltage. Likewise, the data coming into the ESP8266 RXD port will have to be shifted from 1.8/3.3/5V to 3.3V. The device will likely operate at 115200 baud, but it would be nice if the translation worked up to 128000 baud. Most translation ICs I've found have the condition that VCCA<=VCCB, which doesn't work for my use case, as the shifter should work both in "step-up" and "step-down" mode, depending on the reference voltage. Could this problem be solved by using 2 BJT inverters like in the image? Would 2N2222 transistors work? I'm also open to the idea of using a dedicated IC, as various sources have led me to believe it could be a more power efficient and reliable solution. The only problem is finding a suitable IC. Would a SN74LVC1T45 work?