I'm using a Lithium Ion cell (5mAh) at PMIC input for RTC backup. Without any external power supply, this cell is supposed to power RTC domain of iMX6 (we have the iMX6D chipset). SNVS output of PMIC is powering only iMX6 SNVS domain and there is no extra power drain. The theoretical maximum consumption for SNVS domain is 400uA. Which means that the coin cell should last for at least 12 hours. But in practice, it dies after 10mins.
Has anyone seen/experienced anything similar? If so, how did you resolve it?