R2051S01-E2-F

Real Time Clock Overview

The R2051S01-E2-F is a CMOS real-time clock IC manufactured by Nisshinbo Micro Devices, designed for low-power applications with an I2C interface. It operates within a supply voltage range of 0.75V to 5.5V and features a built-in battery backup switchover circuit that automatically switches between main power (VCC) and a backup source (VSB) when VCC drops below the detector threshold (-VDET1). The device includes time and calendar counters in BCD format, two alarm interrupt circuits, and a periodic interrupt generator. It utilizes an SSOP16 package and incorporates internal oscillation stabilization capacitors.

Real Time Clock Feature Summary

• I2C-Bus Interface supporting up to 400kHz clock frequency
• Built-in backup switchover circuit with -VDET1 threshold of 2.40V typical
• Low power consumption: 0.4µA typical at 3V during timekeeping
• Two alarm interrupt circuits (Alarm_W and Alarm_D) and periodic interrupt function

Real Time Clock Applications

• Portable electronic devices requiring precise timekeeping
• Systems utilizing primary or secondary batteries for backup
• Embedded controllers needing I2C-connected real-time clocks

Real Time Clock Procurement Notes

Verify the specific voltage detector threshold (-VDET1) required for the application, as the S01 suffix indicates a 2.40V typical threshold. Confirm compatibility with the SSOP16 package dimensions (5.0mm x 6.4mm x 1.25mm). Ensure the design accounts for the open-drain nature of the SDA and INTR pins, requiring appropriate pull-up resistors for proper I2C operation.

Real Time Clock Selection Notes

Select this model if a 2.40V typical switchover threshold is suitable for the main supply voltage monitoring. Compare with R2051S02-E2-F (2.80V threshold) or R2051S03-E2-F (4.00V threshold) if different monitoring levels are needed. Note that the R2051Txx series lacks the INTR pin and VDCC output, which are present in the S-series.

Real Time Clock Part Context

This component belongs to the R2051 Series of 2-wire interface Real-Time Clock ICs. The 'S' designation specifically identifies the SSOP16 package variant. Other series members include R2051L (QFN), R2051T (TSSOP), and the discontinued R2051K (FFP12). All share similar core functionalities but differ in package type and specific electrical characteristics like voltage detector thresholds.

Real Time Clock Replacement Considerations

Direct replacements within the same family include R2051S02-E2-F and R2051S03-E2-F, provided the different voltage detector thresholds (2.80V and 4.00V respectively) are acceptable for the system design. Cross-package replacements like R2051L01-E2 or R2051T01-E2-F require PCB layout changes and may lack specific pins like INTR.