TXS0102: Is TXS0102 suitable for UART with VCCA=VCCB? if yes, pls kindly help check the schematic

The TXS is a passive switch and does not isolate the signals.

For level shifting, you should use the TXU0202. But for simple buffering, use any two-channel buffer like the SN74LVC2G34.

Hi Ken, 

The TXS0102 can be used to put the I/Os in high-Z when OE is driven low or if VCCA/VCCB is turned off and at 0V. This feature is denoted by IOFF in the datasheet. Note that this device will not redrive your signals similar to what Clemens has mentioned (you may need an I2C buffer instead for that). Please also reference to this app note for further recommendations across different comm. protocols: 

Voltage Translation Application Quick Reference

Regards,

Jack