I'm about to put one of these into a protoboard project and I'm procrastinating about what to do with some of the enables.
https://cdn-shop.adafruit.com/product-files/1787/1787AHC125.pdfI only need 1 channel and I don't need to enable/disable the output. So I was considering simply connecting OE1 to GND.
But the datasheet note:
"To ensure the high-impedance state during power up or power down, OE should be tied to VCC through a pullup
resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver."
Stumped me a bit and presents a problem for me. I'm using the bus transciever to level shift uni-directional between 3.3V and 5V. If I tie OE1 to Vcc via a pull up and then pull it down with the ESP32 once it boots, will that not mean my ESP32 is sinking 5V, which it can't do.
Then there is what to do with the unused OEs and A inputs. If tied all of these to ground, that will enable all buffer channels and send a logic low, meaning the unused outputs are just 0 volts and not floating. Or I could connect the OE's to Vcc and the A inputs to GND, disabling the buffer channels and grounding the input pins.
If I did the later, I would of course need 3 4k7 resistors wouldn't I? You see I'm a bit confused as I expected these inputs to be high impedance inputs which could be directly connected to Vcc, but now I'm not sure.
