Datasheet for the M48T18, a TIMEKEEPER device from ST that combines battery-backed static RAM with a real-time clock in one package. The 144 KB PDF covers pinout, the clock register layout, power-fail behaviour and the external battery connection. Technicians consult it when clock settings or stored configuration are lost, to check the backup battery voltage, chip enable lines and supply switchover. Confirm the full part marking and package on the board before ordering a replacement, as related TIMEKEEPER parts differ in capacity and battery arrangement.
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