Serial RTCs

Like ST's TIMEKEEPER® NVRAMs, Serial RTCs keep track of day-date-time, even in the absence of power. Instead of the standard asynchronous parallel SRAM interface, Serial RTCs use a serial bus. Our devices are available in two industry standard serial interfaces: I²C (Inter-Integrated Circuit) and SPI (Serial Peripheral Interface).


STMicroelectronics ZEROPOWER products integrate low power SRAMs with a power-fail control circuit and a long-life lithium battery. The power-fail circuit monitors the external power supply voltage. If this falls below a specific threshold it automatically write-protects the SRAM and switches the standby power supply to the internal lithium battery. The advantage is long term data retention with fast READ/WRITE times and unlimited READ/WRITE cycles of standard SRAMs.


STMicroelectronics TIMEKEEPER products add a quartz crystal, very low power oscillator and a clock/calendar circuit to provide real-time data. Advanced TIMEKEEPERs include additional features such as programmable alarms, watchdog timers, system reset outputs and battery low warning flags

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