OUTLINE
The R×5C338A are CMOS real-time clock ICs connected to the CPU by three signal lines CE (Chip Enable), SCLK (Serial Clock), and SIO (Serial Input/Output), and configured to perform serial transmission of time and calendar data to the CPU. These models incorporate different functional circuits.

FEATURES
• Timekeeping supply voltage ranging from 1.45 to 5.5 volts
• Low supply current: TYP. 0.35µA (MAX. 0.8µA) at 3 volts (at 25˚C)
• Only three signal lines (SCLK, SIO, and CE) required for connection to the CPU. Maximum clock frequency of 2 MHz (with VDD of 5 volts)
• Time counters (counting hours, minutes, and seconds) and calendar counters (counting years, months, days, and weeks) (in BCD format)
• 1900/2000 identification bit for Year 2000 compliance
• Interrupt circuit configured to generate interrupt signals (with interrupts ranging from 0.5 seconds to 1 month) to the CPU and provided with an interrupt flag and an interrupt halt circuit
• 2 alarm circuits (Alarm_W for week , hour , and minute alarm settings and Alarm_D for hour and minute alarm settings)
• 32-kHz clock circuit (CMOS output, equipped with a control pin)
• Oscillation halt sensing circuit which can be used to judge the validity of internal data
• Supply voltage monitoring circuit with two supply voltage monitoring threshold settings
• Automatic identification of leap years up to the year 2099
• Selectable 12-hour and 24-hour mode settings
• Built-in oscillation stabilization capacitors (CG and CD)
• High precision oscillation adjustment circuit
• CMOS process
• Ultra-compact 10-pin SSOP (RS5C338A with a height of 1.25mm and size of 6.4×3.5mm)
    Ultra-compact 10-pin SSOP-G (RV5C338A with a height of 1.20mm and size of 4.0×2.9mm)