3-WIRE SERIAL INTERFACE REAL-TIME CLOCK ICS WITH VOLTAGE MONITORING FUNCTION NO. EA-053-170413 R5C338A OUTLINE The R5C338A 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. 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. 0.35A 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 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. These models come in an ultra-compact 10-pin SSOP (RS5C338A with a height of 1.25mm and a pin pitch of 0.5mm)and 10-pin SSOP-G (RV5C338A 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. 0.35A (MAX. 0.8A) at 3 volts (at 25C) Only three signal lines (SCLK, SIO, and CE) required for connection to the CPU. DD of 5 volts) Maximum clock frequency of 2 MHz (with V 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 6.43.5mm) Ultra-compact 10-pin SSOP-G (RV5C338A with a height of 1.20mm and size of 4.02.9mm) 1R5C338A BLOCK DIAGRAM ALARM W REGISTER COMPARATOR W 32KOUT 32kHz (MIN,HOUR,WEEK) CLKC OUTPUT VDD CONTROL ALARM D REGISTER VOLTAGE COMPARATOR D (MIN,HOUR) DETECT OSCIN DIVIDER VSS TIME COUNTER OSC CORREC DIV (SEC,MIN,HOUR,WEEK,DAY,MONTH,YEAR) -TION OSCOUT OSC ADDRESS ADDRESS SCLK DETECT DECODER REGISTER SIO I/O CONTROL INTR CE INTERRUPT CONTROL SHIFT REGISTER SELECTION GUIDE Part Number is designated as follows: R V 5C338A - E2 - F Part Number R a 5C338A - bb c Code Description Designation of the package. a S: SSOP10 V: SSOP10G bb Designation of the taping type. Only E2 is available. c Designation of the lead plating. 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) 2