OUTLINE
The R×5C348A/B are CMOS real-time clock ICs connected to the CPU by four signal lines CE (Chip Enable), SCLK (Serial Clock), SI (Serial Input), and SO (Serial Output) 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 circuits generate interrupt signals at preset times. The oscillation circuit is driven under constant voltage so that fluctuations in oscillation frequency due to voltage are small and supply current is also small (TYP. 0.35µA for the R×5C348A and 0.55µA for the R×5C348B at 3 volts). 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-kHz clock output function (Nch. open drain) 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. The 32-kHz clock circuit can be disabled by certain register settings for the R×5C348A but cannot be disabled by any register settings for the R×5C348B. Both these models come in an ultra-compact 10-pin SSOP (RS5C348A/B with a height of 1.25mm and a pin pitch of 0.5mm) and 10-pin SSOP-G(RV5C348A/B with a height of 1.2mm and a pin pitch of 0.5mm.)

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) for the R×5C348A
   TYP. 0.55µA (MAX. 1.0µA) at 3 volts (at 25˚C) for the R×5C348B
• Only four signal lines (CE, SCLK, SI, and SO) required for connection to the CPU.
   Maximum clock frequency of 2MHz (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 (Nch. open drain output) The R×5C348A is designed to disable
   32-kHz clock output in response to a command from the host computer and the
   R×5C348B is designed to keep 32-kHz output enabled.
• 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(RS5C348A/B) 10-pin SSOP-G(RV5C348A/B)

APPLICATIONS
• Communication devices (multi function phone, portable phone, PHS or pager)
• OA devices (fax, portable fax)
• Computer (desk-top and mobile PC, portable word-processor, PDA, electric note or video game)
• AV components (portable audio unit, video camera,camera, digital camera or remote controller)
• Home appliances (rice cooker, electric oven)
• Other (car navigation system, multi-function watch)