DS1270AB

5 years minimum data retention in the absence of external power
Data is automatically protected during power loss
Unlimited write cycles
Low-power CMOS operation
Read and write access times as fast as 70 ns
Lithium energy source is electrically disconnected to retain freshness until power is applied for the first time
Full ±10% VCC operating range (DS1270Y)
Optional ±5% VCC operating range (DS1270AB)
Optional industrial temperature range of  -40°C to +85°C, designated IND