TCA9406: For TCA9406DCUR

Both TCA9406 and TXU0304 have overvoltage-tolerant inputs; no current will flow into the supply. See [FAQ] Can the input voltage (Vi) to my logic device be higher than the supply voltage (Vcc)?

Hi Liu,

liu billy said:

1) For TCA9406DCUR, is there a situation where the 1.8V voltage pulled up from the pin flows back to the VCC_A power supply terminal without supplying power to the VCC_A terminal? What is the basis for yes or no ?

According to Clemens FAQ, the IIK value indicates no positive clamping diode in the TCA9406. 

I must mention that there are internal 10k PU resistors to this device connected to the OE pin. However, if VCCA terminal is powered OFF the 10kohm PU resistors are disabled.

liu billy said:

2)For TCU0304RUTR, is there a situation where the 1.8V voltage pulled up from the pin flows back to the VCC_A power supply terminal without supplying power to the VCC_A terminal? What is the basis for yes or no?

TXU0304 has this line in the datasheet: 

Regards,

Tyler