Hi- I am not using the back up supply in a design. I am using the RTC, but it gets initialized every time it powers up, so it doesn't run when powered down. My question is do I need to put a cap on the V_BAK pin?
Thanks
This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
Hi- I am not using the back up supply in a design. I am using the RTC, but it gets initialized every time it powers up, so it doesn't run when powered down. My question is do I need to put a cap on the V_BAK pin?
Thanks
Hi Jerry,
In the Battery Backup System chapter in the MSP430x5xx and MSP430x6xx Family User's Guide, you can learn more about how the RTC_B module is powered by the battery backup system when the main power supply fails. If you're not providing power to the VBAT pin or have a large supercapacitor there, it makes sense that the RTC does not continue working when you power down your system. The capacitance on VBAK is important for decoupling during switching between primary and backup supplies.
Regards,
James
James,
Thank You, Okay, since I am not using a back up supply and don't care about the RTC when main power is off, I'll remove the cap.
Jerry
**Attention** This is a public forum