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R2061 Series

3-wire Serial Interface Real Time Clock (RTC) with Battery Backup Switch-over Function

  • PLP
  • RoHS

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.

Specs & Datasheets

Timekeeping Supply Voltage Range 1.0 V to 5.5 V
Minimum Timekeeping Supply Voltage Typ. 0.75 V
Supply Current Typ. 0.4 µA
Connection to CPU Three Signal Lines (CE, SCLK, SIO), Maximum Clock Frequency: 1 MHz
Package QFN023023-16, SSOP16
Backup Switchover Voltage 1.7 V, 2.4 V, 2.8 V

Download Datasheet

Protections / Functions

Functional Description

ECO Clock Adjust OSC Halt Sensing Supply Voltage Monitoring Circuit Automatic Identification of Leap Years Selectable 12-hour and 24-hour Backup Switch

Technical Documents

Block Diagram

Quality & Packages

Product Name Compatibility Package Marking Reliability
  • gradeConsumerC
QFN023023-16 R2061L R2061L
  • gradeConsumerC
  • plpP
SSOP16 R2061S R2061S-F

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.

Sample / Buy

Functional Description

ECO ECO Function
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

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