SN74LV245A as level shifter: How to use the ~OE pin

The ~OE pin on the SN74LV245A defines whether to enable the outputs on the chip. Which pins are inputs and which are outputs is defined by the DIR pins, see SN74LV245A as level shifter: How to use DIR pin for more information.

  • If ~OE is low (i.e. connected to GND), all output pins are enabled
  • If ~OE is high (i.e. connected to Vcc), all output pins are disabled

Note that there is no way to disable individual output pins for the SN74LV245A. You can only enable or disable all the pins together.

In most applications as a level shifter, you want to always enable the output: In order to do that, connect the ~OE pin to GND.