In what order should the voltage level translation IC (level shifter) of the dual power supply type be powered up and the signals input?

Start the control circuit first, followed by the other circuitry. Then, apply the control signals to place internal logic in a steady state and then apply other signals. The order is similar for bidirectional dual-power level shifters (buffer type) and unidirectional dual-power level shifters (buffer type).

Apply power supply and other signals in the following order. (Fig. 1)

    #1. VCCA　(power supply for circuit blocks with control circuits)
    #2. VCCB (VCCA and VCCB may be powered up simultaneously.)
    #3. Control signals (/OE, DIR)
    #4. Input signals (A1 or B1)

Fig. 1 Dual supply level shifter (Buffer type）
Fig. 1 Dual supply level shifter (Buffer type）
Fig. 2 Dual supply level shifter (Bus switch type)
Fig. 2 Dual supply level shifter (Bus switch type)

The same order applies to the level shifter (bus switch type). (Fig. 2)

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