This is probably a simple question but a little experience or advice would be great. I am designing a new system using a micro-controller and a few other bits but it turns out to battery back up the RTCC and nothing else is quite tricky and it is probably simpler and cheaper to just use a separate RTCC chip.
With this in mind i am going to use the AB8013 chip which has provision to charge a backup source with automatic switch-over if the main power fails.
I am currently looking at super capacitors for this purpose but i am not sure what voltage i need. All of the super capacitors seem to be rated quite low. The circuit itself is using 3.3V so is a 3.3V Super Capacitor acceptable?
Normally for an electrolytic capacitor i would give lots of margin on the voltage but to do that here i would have to put two of these capacitors in series and i don't have the board space.
I read elsewhere that normally super capacitors can be used at their rated voltage no problem,
The ceramic "supercap" is quite nice. But even with very low current consumption of the Abracon RTC, it will provide backup only for a few days. That may be too short for many applications.
The Abracon RTC doesn't recharge the capacitor, you need an external low leakage diode.
The ceramic "supercap" is quite nice. But even with very low current consumption of the Abracon RTC, it will provide backup only for a few days. That may be too short for many applications.
The Abracon RTC doesn't recharge the capacitor, you need an external low leakage diode.