TIMEKEEPER supervisors convert standard low-power SRAM devices into non-volatile memory. They provide control and battery backup from 1Mbit to 16Mbit external low power SRAM with up to 10 years of data retention, depending on the supervisor, battery and SRAM type selected.
Battery with Crystal Option
ST's removable/replaceable SNAPHAT® battery top contains a Lithium coin cell battery and a 32KHz crystal. It is compatible with all of ST's real-time clocks and TIMEKEEPER® devices in the surface mount SOH-28 and SOH-44 packages.
The SNAPHAT top is designed to be "snapped on" after the SOIC is surface mounted on the PC board. Thus the two piece solution prevents the battery and crystal from being exposed to the high temperatures of the surface mount process.
To evaluate the battery capacity consumption and lifetime: Real-time clocks and TIMEKEEPERs battery life calculation