The DS3800 Battery Cap is a snapon lithium power source for Dallas Semiconductors 40mm ballgrid array (BGA) Nonvolatile SRAM modules. After a host BGA module has been soldered in place and cleaned, the DS3800 Battery Cap is snapped onto the module to serve as the secondary power supply. The Battery Cap is keyed to prevent incorrect attachment and is designed to maintain mechanical and electrical contact with its host module even during severe shock and vibration. Electrically, the DS3800 battery is connected to the host BGA module with goldplated round pins in the Battery Cap inserted into goldplated receptacles on the BGA. Mechanically, four flanges on the DS3800 tightly grip the BGA module board to prevent Cap removal, while corner features in the Cap prevent lateral movement of the Cap while it is attached to its host BGA module.