NUCLEO-F767ZI, switching power supply as external source

[HowMakeWork]

 

Hi, looking to power the NUCLEO-F767ZI off another board (which has a TPSM843320 buck), any issues with this as the 5V rail (E5V), on the dev board you have LD1117 LDO, but the rail I can provide isn’t high enough for the dropout. 

 

Any spec on ripple or how clean the E5V rail should be? Seems to only be used by STLINK and USB.

[FBL]

Hi ​@HowMakeWork 

If your external rail on E5V can fall below 4.75 V, it is not considered acceptable for the E5V input.