RS5C372A/B 2 I C bus SERIAL INTERFACE REAL-TIME CLOCK IC NO.EA-044-160219 OUTLINE The RS5C372A is a CMOS type real-time clock which is connected to the CPU via 2-wires and capable of serial transmission of clock and calendar data to the CPU. The RS5C372A can generate various periodic interrupt clock pulses lasting for long period (one month), and alarm interrupt can be made by days of the week, hours, and minutes by two incorporated systems. Since an oscillation circuit is driven at a constant voltage, it undergoes fluctuations of few voltage and consequently offers low current consumption (Typ. 0.5A at 3V). It also provides an oscillator halt sensing function applicable for data validation at power-on and other occasions and 32-kHz clock output for an external micro computer. (Nch. open drain output) The product also incorporates a time trimming circuit that adjusts the clock with higher precision by adjusting any errors in crystal oscillator frequencies based on signals from the CPU. The crystal oscillator may be selected from 32.768kHz or 32.000kHz types. Integrated into an ultra compact and ultra thin 8 pin SSOP package, the RS5C372A is the optimum choice for equipment requiring small sized and low power consuming products. FEATURES Time keeping voltage: 1.3V to 6.0V Lowest supply current: 0.5 A Typ. (0.9 A Max.) : 3V (25 C) (1.0 A Max.) : 3V ( 40 to 85 C) 2 Connected to the CPU via only 2 wires (I C bus Interface, Max.400kHz, address 7bit) A clock counter (counting hours, minutes, and seconds) and a calendar counter (counting leap years, years, months, and days of the week) in BCD codes Interrupt to the CPU (period of one month to one second, interrupt flag, interrupt halt function)( INTRA , INTRB ) Two systems of alarm functions (days of the week, hours, and minutes) ( INTRA , INTRB ) Oscillation halt sensing to judge internal data validity Clock output of 32.768kHz (32.000kHz) (output controllable via a register) (Nch. open drain output) Second digit adjustment by 30 seconds Automatic leap year recognition up to the year 2099 12-hour or 24-hour time display selectable Oscillation stabilizing capacity (CG, CD) incorporated High precision time trimming circuit Oscillator of 32.768kHz or 32.000kHz may be used CMOS logic Package: 8pin SSOP 1 RS5C372A BLOCK DIAGRAM ALARM A REGISTER COMPARATOR A (WEEK,MIN,HOUR) 32kHz OUTPUT VDD CONTROL ALARM B REGISTER COMPARATOR B (WEEK,MIN,HOUR) OSCIN DIVIDER TIME COUNTER OSC CORREC DIV (SEC,MIN,HOUR,WEEK,DAY,MONTH,YEAR) VSS -TION OSCOUT OSC ADDRESS ADDRESS SCL DETECT DECODER REGISTER INTRA I/O CONTROL SDA INTRB INTERRUPT CONTROL SHIFT REGISTER SELECTION GUIDE Part Number is designated as follows: R S 5C372A - E2 - F Part Number R a 5C372A - bb - c Code Description Designation of the package. a S: SSOP8 bb Designation of the taping type. Only E2 is available. Designation of the lead plating. c F: Lead free plating FB: Sn-Bi plating 2