SN74LVC1G3157: Output terminal when the power is off

The absolute maximum ratings say that you must not exceed V_CC. If you apply a voltage when powered off, a current will flow through the clamping diodes into V_CC and might power up the device, or anything else connected to V_CC.

Thanks for your question.

Are you looking for a switch that will be high-Z when the switch is powered-off? This is a feature called powered-off protection. SN74LVC1G3157 does not have powered-off protection, and as Clemens mentioned, is at risk of back-powering if a voltage is applied on I/O pins when powered-off. 

What is your use case for needing a high-Z state switch when powered-off? Take a look at TS5A3159A which has powered-off protection and is pin-compatible with SN74LVC1G3157 and let me know what you think.

In addition, let me share with you some resources that provide more detail on powered-off protection and how to identify and search for a switch with powered-off protection.

• [Application note] Eliminate power sequencing with powered-off protection signal switches
• TI Precision Labs video: Powered-off protection

Best regards,
Kate

Kate,

I wanted to take measures against one-sided power supply by wrapping around to the connected external sensor.
I would like to consider using the "TS5A3159A" that you have proposed.

thanks a lot for your help,

Toshiyuki Yoshizawa