R2051S03-E2-F

Real Time Clock Overview

The R2051S03-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, a periodic interrupt circuit with selectable frequencies, and a 32.768kHz clock output. It includes a voltage detector with a typical threshold of 4.00V for the R2051S03 variant, oscillation adjustment capabilities, and automatic leap year identification up to 2099.

Real Time Clock Feature Summary

• I2C-Bus Interface: Connects via SCL and SDA lines with support for fast mode up to 400kHz.
• Backup Switchover: Automatic switching between main supply (VCC) and backup battery (VSB) monitored by internal voltage detector.
• Low Power Consumption: Typical timekeeping current of 0.4µA at VDD=3V; minimum operating voltage 0.75V.
• Integrated Functions: Includes dual alarm circuits, periodic interrupts (0.5s to 1 month), 32kHz clock output, and high-precision oscillation adjustment.

Real Time Clock Applications

• Real-time clock modules requiring precise timekeeping with battery backup.
• Systems needing periodic interrupt signals for CPU scheduling or monitoring.
• Applications utilizing I2C communication for compact embedded designs.
• Devices 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 the '03' suffix indicates a typical threshold of 4.00V. Confirm compatibility with the SSOP-16 package dimensions (5.0mm x 6.4mm x 1.25mm). Ensure pull-up resistors are correctly placed on SCL and SDA lines for proper I2C operation. Check that the backup power source matches the switchover requirements.

Real Time Clock Selection Notes

Select this model if a higher voltage detector threshold (approx. 4.00V) is needed compared to other variants like R2051S01 (2.40V) or R2051S02 (2.80V). The SSOP-16 package is suitable for surface mount applications requiring moderate pin count. Consider the R2051Txx series if the INTR pin is not required or if a smaller TSSOP-10 package is preferred, noting that Txx variants lack the VDCC output pin.

Real Time Clock Part Context

The R2051S03-E2-F belongs to the R2051 Series of 2-wire interface Real-Time Clock ICs. This series differentiates models primarily by package type (SSOP16, TSSOP10G, QFN023023-16, FFP12) and voltage detector threshold settings. The 'S' designation specifically refers to the SSOP-16 package. The 'E2' suffix denotes the taping type, and 'F' indicates lead-free plating.

Real Time Clock Replacement Considerations

Direct replacements within the same series include R2051S01-E2-F and R2051S02-E2-F, which share the SSOP-16 package but have different voltage detector thresholds (2.40V and 2.80V respectively). For package changes, R2051L0x-E2 (QFN) or R2051T0x-E2-F (TSSOP) may be considered, though functional differences exist such as the absence of the INTR pin in TSSOP variants.