Low supply current, Small package, 2-wire (I2C Bus) Serial Interface Real Time Clock (RTC)
The R2221 is a CMOS real-time clock IC connected to the CPU by two signal lines, SCL, SDA, and configured to perform serial transmission of time and calendar data to the CPU. The periodic interrupt circuit is configured to generate interrupt signals with six selectable interrupts ranging from 0.5 seconds to 1 month. The 2 alarm interrupt circuits generate interrupt signals at preset times. As the oscillation circuit is driven under constant voltage, fluctuation of the oscillator frequency due to supply voltage is small, and the time keeping current is small (TYP. 0.18 µA at 3V). The oscillation halt sensing circuit can be used to judge the validity of internal data in such events as power-on; the supply voltage monitoring circuit is configured to record a drop in supply voltage below supply voltage monitoring threshold settings. The 32.768kHz clock output function (CMOS output with control pin) is intended to output sub-clock pulses for the external microcomputer. The oscillation adjustment circuit is intended to adjust time counts with high precision by correcting deviations in the oscillation frequency of the crystal oscillator. Since the package for these ICs are TSSOP10G or QFN018018-12, high density mounting of ICs on boards is possible.
Timekeeping Supply Voltage Range 0.9 V to 5.5 V Minimum Timekeeping Supply Voltage Typ. 0.6 V Supply Current 0.3 µA Connection to CPU I2C Bus Serial Interface (SCL, SDA) Clock Output 32.768 kHz (CMOS Output with Control Pin) Package QFN018018-12, TSSOP10G ECO Mode Configurable by Pins
Protections / Functions
ECO Clock Adjust OSC Halt Sensing Supply Voltage Monitoring Circuit Automatic Identification of Leap Years Selectable 12-hour and 24-hour Backup Switch
- Refer to the datasheets for the details on the product.
- The package file includes package dimensions, taping specifications, taping reels dimensions, power dissipations, and recommended land pattern.
- Please contact us or our distributors for unpublished reliability information.
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|Clock Adjust||Clock Adjust Function|
|OSC Halt Sensing||OSC Halt Sensing Function|
|Supply Voltage Monitoring Circuit||Supply Voltage Monitoring Function|
|Automatic Identification of Leap Years||Automatic Identification of Leap Years|
|Selectable 12-hour and 24-hour||Selectable 12-hour and 24-hour|
|Built-in VD with Delay Time||Built-in VD with Delay Time|