The R2061 is a CMOS real-time clock IC connected to the CPU by three signal lines, CE, SCLK, and SIO, and configured to perform serial transmission of time and calendar data to the CPU. Further, battery backup switchover circuit and a voltage detector. 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. 0.4µA 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 two selectable supply voltage monitoring threshold settings. The oscillation adjustment circuit is intended to adjust time counts with high precision by correcting deviations in the oscillation frequency of the quartz crystal unit. Battery backup switchover function is the automatic switchover circuit between a main power supply and a backup battery of primary or secondary battery. Switchover is executed by monitoring the voltage of a main power supply, therefore the voltage of a backup battery voltage is not relevant. Since the package for these ICs is SSOP16 and QFN023023-16, high density mounting of ICs on boards is possible.
|Minimum Timekeeping supply voltage||TYP. 0.75 V|
|Supply Current||TYP. 0.4 µA|
|Connected to the CPU||Three signal lines (CE, SCLK, and SIO), Maximum clock frequency of 1MHz (with VCC = 3V)|
|Functions||Time counters (counting hours, minutes, and seconds) and calendar counters (counting years, months, days, and weeks) (in BCD format)|
|Interrupt circuit configured to generate interrupt signals (with interrupts ranging from 0.5 seconds to 1 month) to the CPU and provided with an interrupt flag and an interrupt halt|
|2 alarm interrupt circuits (Alarm_W for week, hour, and minute alarm settings and Alarm_D for hour and minute alarm settings)|
|With Power-on flag to prove that the power supply starts from 0V|
|Supply voltage monitoring circuit with two supply voltage monitoring threshold settings|
|Automatic identification of leap years up to the year 2099|
|Selectable 12-hour and 24-hour mode settings|
|Built-in Circuits||Backup switchover circuit (can be used for a primary battery, a secondary battery, or an electric double layer capacitor)|
|Voltage detector with delay|
|Oscillation stabilization capacitors (CG and CD)|
|High precision oscillation adjustment circuit|
*) Tab is VSS level. The tab is better to be connected to the VSS.
PRODUCT LONGEVITY PROGRAM
R2061S operate PRODUCT LONGEVITY PROGRAM (ten-year supply is maintained as of January, 2016).
This program has been introduced to help customers select the most appropriate part for applications that require long life cycles.
In the R2061 Series, the package and the output voltage can be designated.
|Product Name||Package||Quantity per Reel|