R2051S02-E2-F

Real Time Clock Overview

The R2051S02-E2-F is a CMOS real-time clock IC from Nisshinbo Micro Devices, housed in an SSOP-16 package. It features a 2-wire I2C interface (400kHz) for time and calendar data transmission. Key specifications include a minimum timekeeping voltage of 0.75V typ., low power consumption of 0.4µA typ. at 3V, and built-in backup switchover circuitry. The device incorporates two alarm interrupt circuits, periodic interrupts, and a voltage detector with a threshold of 2.80V typ. It supports automatic leap year identification up to 2099 and includes high-precision oscillation adjustment capabilities.

Real Time Clock Feature Summary

• I2C-Bus Interface: Connects via SCL and SDA lines with support for 400kHz fast mode.
• Backup Switchover: Automatic switching between main supply (VCC) and backup battery (VSB) monitored by internal voltage detector.
• Alarm & Interrupts: Features Alarm_W (week/hour/minute) and Alarm_D (hour/minute) circuits, plus selectable periodic interrupts from 0.5s to monthly.
• Precision Timing: Includes high-precision oscillation adjustment circuit correcting deviations up to ±1.5ppm or ±0.5ppm.

Real Time Clock Applications

• Embedded systems requiring accurate timekeeping with low power consumption.
• Devices utilizing primary batteries, secondary batteries, or capacitors for backup power.
• Systems needing automatic leap year correction up to the year 2099.
• Applications requiring voltage monitoring and power-on reset flag functionality.

Real Time Clock Procurement Notes

Verify the specific voltage detector threshold setting (-VDET1) required for the application, as this variant uses a 2.80V typ. threshold. Confirm compatibility with the SSOP-16 package dimensions (5.0mm x 6.4mm x 1.25mm). Ensure pull-up resistors are appropriately selected for the I2C bus speed and voltage levels. Check lead plating specifications if environmental compliance beyond standard RoHS is required.

Real Time Clock Selection Notes

Select the R2051S02-E2-F when a 2.80V typical switchover threshold is needed, distinguishing it from the S01 (2.40V) and S03 (4.00V) variants. This model is suitable for designs where the main supply voltage drops below 2.8V before backup activation is desired. Consider the SSOP-16 package constraints regarding board space compared to QFN or TSSOP options within the same series.

Real Time Clock Part Context

This component belongs to the R2051 Series of 2-wire interface Real-Time Clock ICs. The 'S' designation indicates the SSOP-16 package type. The '02' suffix specifies the voltage detector threshold setting of 2.80V typ. The 'E2' denotes the taping type, and 'F' indicates lead-free plating. Other series members include R2051Lxx (QFN), R2051Txx (TSSOP), and discontinued R2051Kxx (FFP12).

Real Time Clock Replacement Considerations

Direct replacements within the same series require matching the package and voltage threshold. For SSOP-16 packages, consider R2051S01-E2-F (2.40V threshold) or R2051S03-E2-F (4.00V threshold) depending on the system's power supply characteristics. Cross-package replacements like R2051L02-E2 (QFN) or R2051T01-E2-F (TSSOP) require schematic and PCB layout modifications due to pinout and physical dimension differences.