TMS570LC4357: Backpower through OSCIN pin

Hello Stephen,

If the MCU is powered off, the input buffer is not enabled.

I am concerned about backpowering the device through ESD diodes, as discussed in this article: 

Back powering: Why are the lights on when the power is off?

You have your new logic circuit running and everything works as designed. Then you turn off the power and the circuit continues to work. What is going on? In today’s world, with all the plug-and-play…

By Chris Cockrill over 11 years ago in Technical articles > Analog

I don't see why a CLK input would have ESD clamp diodes to VDD, but I want to make sure of that as I can't find anything in the datasheet about it.  Thanks

Hello Stephen,

If you use an external oscillator clock source rather than a crystal, the device may be back-powered if applying clock signal to OSCIN prior to powering it up. I will double check with design guy.

Thanks for looking into this.  I appreciate it.

Steve