Common Ground different ldo

Thread Starter

barg

Joined Dec 23, 2015
111
Hello,

I am using a few circuits/boards - All communicate between them with i2C (with sufficient pullups) to 1 of them that includes the mcu. and rest of the boards are for controlling sensors. in each of the boards there is a 3.3v Voltage regulator that output max 0.5A. All the boards feeds from the same 12vin and the same ground (common ground for all).

My Question is, is it optimal to use individual LDO 3.3v voltage regulator in each of the separate boards as noted?

Thank you in Advace!
 

Ian0

Joined Aug 7, 2020
9,428
Hello,

I am using a few circuits/boards - All communicate between them with i2C (with sufficient pullups) to 1 of them that includes the mcu. and rest of the boards are for controlling sensors. in each of the boards there is a 3.3v Voltage regulator that output max 0.5A. All the boards feeds from the same 12vin and the same ground (common ground for all).

My Question is, is it optimal to use individual LDO 3.3v voltage regulator in each of the separate boards as noted?

Thank you in Advace!
From the I2C interface's point of view it doesn't matter. Provided that the pullups pull the voltage high enough to register a high logic level it will work.
I2C will still work with a mixture of 3.3V and 5V logic.
Separate regulators may be better for other circuit functions.
 

Thread Starter

barg

Joined Dec 23, 2015
111
Hi Ian,

Thanks for your reply.

Can you please clarify why " Separate regulators may be better for other circuit functions."? my intention is to deliver accurate 3.3v in each seperate board, did you meant to that?
 

Ian0

Joined Aug 7, 2020
9,428
Hi Ian,

Thanks for your reply.

Can you please clarify why " Separate regulators may be better for other circuit functions."? my intention is to deliver accurate 3.3v in each seperate board, did you meant to that?
For instance, if you have digital parts of your circuit and analogue parts, then separate regulators would improve noise. I2C would still work.
 

BobTPH

Joined Jun 5, 2013
8,642
Distributing the 3.3V from a central point would likely cause MORE variation in the voltages than separate regulators since there would be voltage drops across the wiring.
 
Top