Maxim DS3231M+ breakout

Community PCB Design
1

I’ve been working on designing a breakout board for the Maxim DS3231M+ RTC and I’ve got the schematic finished ( i think ) and I had a quick question about the backup battery. Does the GND of the CR1220 get connected to the GND of the main power supply?

Currently, I’m planning on connecting 5v off arduino to VCC (pin 2) and all the GND pins (5-13) to GND on the arduino via the headers CN1 and CN2. Would I just tie GND from the CR1220 to the pins/header pin effectively connecting all grounds together, or does the batteries ground need to be separate from the supply voltage ground?

http://koberg.hackhut.com/files/2011/04/schematic2.png

Also, I’ve changed the orientation of the CR1220 since uploading this image so the +V and GND are facing the right way. I just haven’t had a chance to update the image.

2

Yes, the battery GND needs to be connected to the main GND. Also, you need to place 0.1uF cap in parallel with C1 and place it as close as possible to DS3231.