MPM3610: Power on V_Out when there is no power is on V_In

I’m building a circuit that requires 12VDC and 5VDC. I’m using the MP3610 with the typical application circuit (figure 11 in the datasheet) to reduce 12VDC to 5VDC. On occassion (mostly during testing) I’d like to run the board with 5VDC only and forgo using the components that requires 12VDC. How will the MP3610 behave with V_Out @ 5VDC and V_In floating? Since EN will be floating in that condition, I’m assuming that the chip will be disabled. Do you recommend the placement of a diode to protect it from back driving?

Thanks for your help,

Hi Josh, welcome to the forum!

Correct, you can float the EN pin to disable the MPM3610. There should be no problem having 5V on Vo while the device is disabled.

Thanks for your response!