TCA9548A: Data and Clock lines behavior - while Vcc is off

Sunset said:

Part Number: TCA9548A

Hello Team,

we are using the TCA9548A and we have test scenario, where there would be a need to power off Vcc to the TCA9548A  and drive the SCL and SDA lines from an external programmer connected to the board.

• Can you confirm that the TCA9548A lines (SD0, SC0) can withstand a voltage on the inputs while the TCA9548A  does not get any voltage?
  • [Bobby] The device is 5V tolerant on the I/O pins. As long as you don't violate the absolute max ratings of the device, you should not see damage (even while Vcc is not present)
• Can you confirm that the TCA9548A  does not pull/hold neither high or low the data and clock lines if the device is not powered?
  • [Bobby] Yes, the device will not latch the pins when it is unpowered as long as you don't violate the absolute max ratings. 
• Can you confirm that the internal switch will keep the SDA, SCL lines disconnected from the SD0 and SC0 lines while Vcc is off?
  • [Bobby] Again, Yes as long as the absolute max ratings of the device are not violated. Things like large negative transients could damage the device's pins and this would no longer hold true which is why I keep pointing back to the absolute max ratings. If you keep the device within the spec limit, then there should be no problem.

Thanks for the follow up,

SunSet