The design of the output-enable (OE) input circuit is referenced to VCCA so that all outputs are placed in the high-impedance state when the OE input is high. To put the outputs in a high-impedance state during power up or power down, the OE input pin must be tied to V_CCA through a pullup resistor and must not be enabled until V_CCA and V_CCB are fully ramped and stable. The current-sinking capability of the driver determines the minimum value of the pullup resistor to V_CCA.

V_CCA or V_CCB can be powered up first. If the SN74AVCH8T245 is powered up in a permanently enabled state
(for example OE is always kept low), then pullup resistors are recommended at the input. Doing this allows for proper, glitch-free, power-up. For more information, see Designing with SN4LVCXT245 and SN74LVCHXT245 Family of Direction Controlled Voltage Translators/Level-Shifters. In addition, the OE pin may be shorted to GND if the application does not require use of the high-impedance state at any time.