We are planning to use PCF85263AT in our design for RTC and Watchdog Reset Out features. We have connected VDD to 1.8V supply and the I2C SCL and SDA lines are also pulled up to 1.8V supply. We have connected the VBAT to a 3V battery supply. As per datasheet, we understand that all supplies are within range. Also, as default battery power switch-over threshold is 1.5V, there should not be any issue with a higher voltage battery. Can you please confirm, if this scheme is fine or do you see any issues with this?