Specifications

Theory of Operation
b) Minimum Data Retention Time:
Total Current Drain = Clock + RAM + Buffer
= 1uA+50uA+80uA
= 111 uA
Battery Life = 1 AHr x 1 Day x 1
----- ---
(24-8)Hr 111 uA
= 563 Days (1.5 years)
2. Real-time clock, 32 Kbyte static RAM, one 128 Kbyte static
RAM (monolithic part assumed)
a) Typical Data Retention Time:
Total Current Drain = Clock + RAM + Buffer + 128 Kbyte RAM
= 1uA+1uA+8uA+1uA
=11uA
Battery Life = 1 AHr x 1 Day x 1
----- ---
(24-8)Hr 11 uA
= 5896 Days (16.1 years)
Note: Again, the typical shelf life is 10 years, which would
become the limit here.
b) Minimum Data Retention Time:
Total Current Drain = Clock + RAM + Buffer + 128 Kbyte RAM
= 1uA+50uA+80uA+50uA
= 181 uA
Battery Life = 1 AHr x 1 Day x 1
----- ---
(24-8)Hr 181 uA
= 345 Days (.95 years)
3-24