The R2043K/T is a CMOS real-time clock IC connected to the CPU by four signal lines, CE, SCLK, SI, SO, and configured to perform serial transmission of time and calendar data to the CPU. The periodic interrupt circuit is configured to generate interrupt signals with six selectable interrupts ranging from 0.5 seconds to 1 month. The 2 alarm interrupt circuits generate interrupt signals at preset times. As the oscillation circuit is driven under constant voltage, fluctuation of the oscillator frequency due to supply voltage is small, and the time keeping current is small (TYP. 0.45µA at 3V). The oscillation halt sensing circuit can be used to judge the validity of internal data in such events as power-on; The supply voltage monitoring circuit is configured to record a drop in supply voltage below two selectable supply voltage monitoring threshold settings. The 32.768kHz clock output function (N-channel open drain output) is intended to output sub-clock pulses for the external microcomputer. The oscillation adjustment circuit is intended to adjust time counts with high precision by correcting deviations in the oscillation frequency of the crystal oscillator. Since the package for these ICs are TSSOP10G (4.0x2.9x1.0: R2043T) or FFP12 (2.0x2.0x1.0: R2043K), high density mounting of ICs on boards is possible.
This document is a technical datasheet for the Ricoh R2043K/T series of CMOS real-time clock integrated circuits. The device connects to a CPU via four signal lines (CE, SCLK, SI, SO) to perform serial transmission of time and calendar data.
Key features include periodic interrupt generation with six selectable ranges from 0.5 seconds to one month, two alarm interrupt circuits for preset times, and low power consumption typical at 0.45uA when the supply voltage is 3V. The IC also includes a 32-kHz clock output function and an oscillation adjustment circuit for high precision.
| Timekeeping supply voltage (Typ) | 0.66 to 5.5V |
|---|---|
| Low power consumption (Typ at 3V) | 0.45uA |
| Oscillation Frequency | 32.768 kHz |
| Operating Temperature Range | -40 to +85 °C |
| Package Type R2043K | FFP12 (2.0mm x 2.0mm x 1.0mm) |
| Package Type R2043T | TSSOP10G (4.0mm x 2.9mm x 1.0mm) |
The typical timekeeping current is 0.45uA when VDD=3V.
The R2043K uses an FFP12 package and the R2043T uses a TSSOP10G package.
The maximum operating temperature is +85 °C.