Can I feed external power to VADJ on my Genesys2 development Kit?

[Tifei]

In Genesys2 Development Kit VADJ has 4 options: 1.2V 1.8V 2.5V 3.3V which controlled by JP6. I would like to apply an external power supply with a fine tune feature to VADJ on my Genesys2 Development Kit. The purpose is to scan I/O voltage with a 10% range at 1.5V(1.40 ~ 1.60V) and 1.8V(1.70 ~ 1.90V) then see the influence on I/O performance. Checking the schematics page 20, I found I can remove R408, then solder my power wire on it. But I see a current/power monitor IC34 is connected to R408 as well.

Will removing R408 bring trouble to IC34 and IC37 power regulator? Will this modification create trouble to my Genesys2 board?

Please advice, thanks.

 

 

[JColvin]

Hi Tifei,

I have asked some of our applications engineers about this. They will get back to you here on the forum.

Thanks,
JColvin

[Bianca]

Hello Tifei,

It is right, if you remove R408 you can power VDAJ with external power source. Once you've removed the resistance, IC37 will be left open, won't power anything and IC34 won't measure the current anymore. You have to take care of the circuits that are powered from VADJ, to be compatible with the voltage value you want to bring from your external source. Also you have to respect the power-up/power-down sequence with the other internal power sources. For example, it's not recommended to turn off the board with VADJ externally powered. 

Best regards,

Bianca