(Battery Backed SRAM) SRAM memory that is backed up with a lithium battery in the event of power failure. "Discrete BBSRAM" places SRAM chips on a small printed circuit board (PCB) along with the battery and switchover circuit. The PCB is typically around 60 square inches. "BBSRAM modules" encapsulate the SRAM, battery and circuitry into chip packages that are smaller than the discrete BBSRAM boards. See nvSRAM and solid state drive.