R2061L03-E2

Real Time Clock Overview

The R2061L03-E2 is a CMOS real-time clock IC from the R2061x series, manufactured by Nisshinbo Micro Devices. It features a 3-wire serial interface (CE, SCLK, SIO) for CPU communication with a maximum clock frequency of 1 MHz at 3V. The device provides time and calendar counters in BCD format, including automatic leap year identification up to 2099. Key electrical parameters include a minimum timekeeping supply voltage of 0.75 V (typical) and a typical timekeeping current of 0.4 µA at 3 V. It incorporates a battery backup switchover circuit triggered when the main supply (VCC) drops below a threshold of 2.80 V (typical). The component is housed in a QFN023023-16 package.

Real Time Clock Feature Summary

• 3-Wire Serial Interface: Connects to CPU via CE, SCLK, and SIO lines, supporting data transfer rates up to 1 MHz.
• Battery Backup Switchover: Automatically switches power from main supply (VCC) to backup source (VSB) when VCC falls below the detector threshold (-VDET1 typ. 2.80 V).
• Low Power Consumption: Typical timekeeping current is 0.4 µA at VDD=3V, with a minimum operating voltage of 0.75 V.
• Integrated Oscillation Circuit: Includes built-in oscillation stabilization capacitors (CG and CD) and a high-precision adjustment circuit for frequency correction.

Real Time Clock Applications

• Embedded systems requiring precise timekeeping with low power consumption.
• Devices utilizing primary batteries (e.g., CR2025) or secondary batteries/capacitors for backup power.
• Applications needing periodic interrupts and alarm functions synchronized with system clocks.

Real Time Clock Procurement Notes

Verify the product status as 'Not For New Designs' before implementation. Confirm that the QFN023023-16 package dimensions (2.3mm x 2.3mm x 0.4mm) fit the target PCB layout. Ensure the backup voltage monitoring threshold of 2.80 V aligns with the system's main supply dropout requirements. Check for lead-free plating availability if required by assembly processes.

Real Time Clock Selection Notes

Select the R2061L03-E2 variant specifically for its 2.80 V backup switchover threshold; other variants like R2061L01-E2 have a 1.70 V threshold. This model uses the QFN023023-16 package, distinct from SSOP16 or FFP12 options. Ensure the application supports the 3-wire serial protocol and can handle the open-drain interrupt output characteristics. Verify compatibility with the internal oscillator capacitor values (10 pF) for the connected quartz crystal unit.

Real Time Clock Part Context

The R2061L03-E2 belongs to the R2061x series of 3-wire interface real-time clock ICs. It is part of the Nisshinbo Micro Devices portfolio, formed from the integration of New Japan Radio and Ricoh Electronics Devices. The 'L' suffix denotes the QFN023023-16 package, while '03' indicates the specific voltage detector setting. This series is designed for high-density mounting and efficient power management in portable electronics.

Real Time Clock Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. The R2061Kxx series (FFP12 package) is discontinued. Designers should evaluate the R2061Sxx series (SSOP16 package) or other R2061L variants (e.g., R2061L01-E2) based on package and voltage threshold requirements, though these are not direct pin-compatible replacements due to different form factors.