STM32L4 VDD vs VDDUSB vs VDDA

[Patrice Favreau]

Posted on May 01, 2018 at 00:12

I am designing with a STM32L4 in QNF48 and would like to save power...

How about

    VDDUSB = 3.3V

    VDDA = 3.3V with linear regulator , VREF = VDDA

    VDD = 1.8V 

    Now the data sheets say  |∆VDDx| must be less than 50mv .

    

    Is this mean all power need to be at the same level +/- 50mv, or that all of the same name need to be within 50mv

 Thanks!!!

[waclawek.jan]

Posted on May 01, 2018 at 10:01

Now the data sheets say  |∆VDDx| must be less than 50mv .

Which datasheets? And how do they exactly describe what |∆VDDx| is?

JW

[Patrice Favreau]

Posted on May 01, 2018 at 10:55

Every STM32 datasheet I ever saw.

So if this is true that all vdd need to be basically the same voltage

Can we use the USB while vdd is not 3.3V?

Thanks

[waclawek.jan]

Posted on May 01, 2018 at 19:55

Every STM32 datasheet I ever saw.

Show (you can paste pictures here).

JW

[Jismal Jamal]

Posted on May 11, 2018 at 09:03

 |∆VDDx| must be less than 50mv  :- Variations between different VDDX power pins of  the same domain

So if VDDIO2 ,VDD ,VDDUSB are of separate domains so no issue as of my knowledge correct me if i am wrong.