TXS0104E: TXS0104E: B port pulled low when device powered down

Part Number: TXS0104E

Hi, Team:

My customer is using TXS0104E and come to below question. Could you please give your comments?

TXS0104E is used as a dual direction level shifter. The A port side is connected to FPGA, and Vcca is powered with 1.8V.  The B port side is connected to PMBUS of DCDC converter, and Vccb is powered with 3.3V.

We find that when 1.8V and 3.3V is not powered up, and even with OE pulled low through resistor, the B port of TXS0104 are still pulled low by TXS0104 all the time.

Due to this, we cannot use external PMBUS debug tool (through 3.3V PMBUS external connector) to connect with the PMBUS of DCDC converter.

 Could you please help to check whether it is reasonable? Or if we want to use external PMBUS tool to connect to B port of TXS0104. Do you think powering up TXS0104 and pull OE low will help?

Thank you so much for your help

Yarn.