Separate analog and digital power supply for PSoC-4M

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
Mrinal
Level 4
Level 4
First solution authored 50 replies posted 25 replies posted

Hi!

   

I was wondering whether is it possible to connect (VSSA and VDDA) to a different supply voltage other than that is being used for (VSSD and VDDD).

   

Also is it possible to connect VSSA to a slightly negative voltage, say -200mV as compared to VSSD which is referenced 0V for digital peripherals.

   

The configuration would look like:

   

VDDD = 3.3V

   

VSSD = 0V

   

VSSA = -0.2V

   

VDDA = 3.1V  (VDDA-VSSA = 3.3V)

   

Thanks

0 Likes
1 Solution
Bob_Marlowe
Level 10
Level 10
First like given 50 questions asked 10 questions asked

Won't work. Vdda must be the highest voltage for the chip.

   

 

   

Bob

View solution in original post

0 Likes
3 Replies
Bob_Marlowe
Level 10
Level 10
First like given 50 questions asked 10 questions asked

Won't work. Vdda must be the highest voltage for the chip.

   

 

   

Bob

0 Likes
Mrinal
Level 4
Level 4
First solution authored 50 replies posted 25 replies posted

Well in that case how about this:

   

VDDD = 3.3V

   

VSSD = 0V

   

VSSA = -0.2V

   

VDDA = 4.8V  (VDDA-VSSA = 5VV)

   

 

   

Are the VDDD and VDDA pins connected internally? (Same for VSSD and VSSA)

   

Also, if the requirement that VDDA must be >= VDDD is fullfilled, then is it OK to have VSSA biased to a slightly negative voltage?

   

This is to take care of saturation of analog peripherals and also to implement differential measurement for voltages that may swing to negative values.

0 Likes
Bob_Marlowe
Level 10
Level 10
First like given 50 questions asked 10 questions asked

That is below the "Absolute Maximum Ratings". You'll need to test for yourself if it has the wanted effect or just a defect 😉

   

 

   

Bob

0 Likes