A TIMEKEEPER Data Retention Lifetime is determined by two factors:

• The battery becoming discharged, having provided current to the SRAM in the battery back-up mode.
• The effects of aging causing the cell to become inoperative before the stored charge has been fully consumed. The current drawn is dependent not only on the temperature but on whether the oscillator is active.

The first effect is known as Capacity Consumption and the second as Storage Life (which is primarily a function of temperature). The two effects have very little influence on each other, being independent but operating simultaneously. The data retention lifetime of the device is determined by whichever occurs first.

TIMEKEEPER devices are packaged in a 600mil DIP CAPHAT™ or a 330mil SOIC SNAPHAT^® , the SNAPHAT having a removable top that includes the long life lithium cell. If a data retention lifetimes greater than calculated is required, the user is advised to select the SNAPHAT package. As the battery reaches the end of its useful life, it is possible to remove the SNAPHAT top containing the nearly expended cell, and to replace it with a fresh unit. No data will be lost during the process, provided that the board remains powered-up during the operation.

Select the package required and click OK. For CAPHAT select the required part number to display Data Retention Lifetime information. For SOIC and SNAPHAT select the part number, temperature rating and battery type then click where indicated to display Data Retention Lifetime information.