Microchip SRAM, 47L64-I/SN- 64kbit

The Microchip EERAM is an SRAM that doesn't lose its content on a power disruption. Inside each memory cell, transparent to the user, are non-volatile transistors that capture the SRAM content and hold it through power loss events. On power restore, the SRAM is reloaded with its last content and SRAM operation can continue.

8,192 x 8 bit Serial SRAM with internal non-volatile data backup
I2C Interface: Up to 3MHz with Schmitt trigger inputs for noise suppression
Low-Power CMOS Technology: Active current: 5 mA (maximum)
Standby current: 500 μA (maximum)
Hibernate current: 3 μA (maximum)
Cell-Based Non-volatile Backup mirrors SRAM array cell-for-cell and transfers all data to/from SRAM cells in parallel (all cells at same time)
Invisible-to-User Data Transfers: VCC level monitored inside device, SRAM automatically saved on power disrupt, SRAM automatically restored on VCC return
100,000 Backups Minimum (at 20°C)
100 years retention (at 20°C)

Datasheet - 47L64-I/SN