Since this is to support a clock, another option is use a Real Time Clock chip with standard coin cell type battery backup.
http://www.dipmicro.com/store/DS1307N
http://www.dipmicro.com/store/BH2025
http://www.dipmicro.com/store/BAT-CR2025
Since this is to support a clock, another option is use a Real Time Clock chip with standard coin cell type battery backup.
http://www.dipmicro.com/store/DS1307N
http://www.dipmicro.com/store/BH2025
http://www.dipmicro.com/store/BAT-CR2025