R2051L02-E2

Real Time Clock Overview

The R2051L02-E2 is a CMOS real-time clock IC from Nisshinbo Micro Devices, housed in a QFN023023-16 package. It interfaces with CPUs via a 2-wire I2C bus (SCL/SDA) supporting up to 400kHz. Key electrical parameters include a minimum timekeeping voltage of 0.75V typ and a timekeeping current of 0.4µA typ at 3V. The device features an automatic battery backup switchover circuit triggered by a supply voltage detector threshold of 2.80V typ (-VDET1). It includes periodic and dual alarm interrupt circuits, a 32kHz clock output, and built-in oscillation stabilization capacitors.

Real Time Clock Feature Summary

• I2C interface with 400kHz fast mode support
• Automatic battery backup switchover with 2.80V detection threshold
• Low power consumption: 0.4µA typical timekeeping current
• Built-in oscillation adjustment circuit for high precision

Real Time Clock Applications

• Battery-backed real-time clock systems
• Embedded devices requiring low-power timekeeping
• Systems utilizing primary or secondary backup batteries

Real Time Clock Procurement Notes

Verify the specific suffix E2 corresponds to the taping type designation as per the manufacturer's selection guide. Confirm that the QFN023023-16 package dimensions align with the target PCB footprint requirements. Ensure compatibility with the 2.80V voltage detector threshold for the main power supply monitoring application.

Real Time Clock Selection Notes

Select this model when a QFN package is required instead of SSOP or TSSOP options within the R2051 series. The '02' serial number indicates a 2.80V typical detector threshold, distinct from the 2.40V threshold found in the R2051L01 variant. Consider the 32kHz clock output pin availability for external microcomputer synchronization needs.

Real Time Clock Part Context

This component belongs to the R2051 series of 2-wire interface Real-Time Clock ICs. The series includes variants with different packages such as SSOP16 (R2051Sxx), TSSOP10G (R2051Txx), and the discontinued FFP12 (R2051Kxx). The L-series specifically utilizes the compact QFN023023-16 package for high-density mounting.

Real Time Clock Replacement Considerations

The R2051L01-E2 serves as a direct package-compatible alternative with a different voltage detector threshold (2.40V typ vs 2.80V typ). Other series members like R2051S02-E2-F offer identical electrical characteristics but in an SSOP16 package.