R2223T-E2-F

Real Time Clock Overview

The R2223T-E2-F is a CMOS real-time clock IC manufactured by Nisshinbo Micro Devices, housed in a TSSOP10G package. It utilizes a 2-wire serial interface (I2C) for communication with a CPU via SCL and SDA lines. The device provides timekeeping and calendar functions using BCD format counters for seconds, minutes, hours, day-of-week, day-of-month, month, and year. Key electrical parameters include a minimum timekeeping voltage of 0.6V to 5.5V and a typical timekeeping current of 0.18µA at 3V. It features two alarm interrupt circuits, periodic interrupts, and a 32.768kHz clock output.

Real Time Clock Feature Summary

• Dual alarm interrupt circuits: Alarm_W supports week/hour/minute settings, while Alarm_D supports hour/minute settings.
• Built-in oscillation stabilization capacitors (CG and CD) allow high-precision frequency adjustment up to ±189ppm.
• Includes power-on reset flag, oscillation halt sensing, and supply voltage monitoring circuits.
• Supports selectable 12-hour and 24-hour modes with automatic leap year identification up to 2099.

Real Time Clock Applications

• Systems requiring low-power real-time clocking with battery backup.
• Embedded devices needing periodic interrupt signals for CPU scheduling.
• Applications utilizing external microcomputers requiring a 32kHz sub-clock output.

Real Time Clock Procurement Notes

Verify the specific suffix 'E2-F' corresponds to the TSSOP10G package and lead-free status as listed in the selection guide. Confirm that the INTRA and INTRB pins are utilized correctly, as this model differs from the R2221x series which lacks these separate interrupt outputs. Ensure pull-up resistors are present on SCL and SDA lines for proper I2C operation.

Real Time Clock Selection Notes

Select the R2223T-E2-F over the R2221T-E2-F if separate interrupt outputs for weekly (INTRB) and daily (INTRA) alarms are required. The R2223x achieves ECO mode via register setting rather than a dedicated pin, offering flexibility in pin usage. Ensure the crystal oscillator's equivalent series resistance is compatible with the selected ECO mode settings for optimal current consumption.

Real Time Clock Part Context

The R2223T-E2-F belongs to the R2223x family of 2-wire serial interface real-time clocks. It shares core functionalities with the R2221x series but distinguishes itself through its pinout configuration, specifically providing separate INTRA and INTRB interrupt pins instead of a single INTR pin. This variant is designed for high-density mounting in compact electronic systems.

Real Time Clock Replacement Considerations

The R2221T-E2-F is a functional alternative within the same family but uses a single INTR pin for all interrupts. Direct pin-to-pin replacement requires software modification to handle combined interrupt sources. Other packages like QFN018018-12 (R2223L-E2) offer different form factors but share identical internal logic.