TXB0108: power sequence between VccA and VccB

This information is in section 10 - Power Supply Recommendations on the datasheet:

During operation, ensure that VCCA ≤ VCCB at all times. During power-up sequencing, VCCA ≥ VCCB does not
damage the device, so any power supply can be ramped up first. The TXB0108 has circuitry that disables all
output ports when either VCC is switched off (VCCA/B = 0 V).

The output-enable (OE) input circuit is designed so that it is supplied by VCCA and when the (OE) input is low, all
outputs are placed in the high-impedance state. To ensure the high-impedance state of the outputs during
power-up or power-down, the OE input pin must be tied to GND through a pulldown resistor and must not be
enabled until VCCA and VCCB are fully ramped and stable. The minimum value of the pulldown resistor to ground
is determined by the current-sourcing capability of the driver.