Ricoh RS5C372A Manual

2
I C bus SERIAL INTERFACE REAL-TIME CLOCK IC
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. 0.5μA 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: 0.5μA Typ. (0.9μA Max.) : 3V (25°C)
•
Connected to the CPU via only 2−wires (I
•
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 (C
•
High precision time trimming circuit
•
Oscillator of 32.768kHz or 32.000kHz may be used
•
CMOS logic
•
Package: 8pin SSOP
(1.0μA Max.) : 3V (−40 to +85°C)
2
C bus Interface, Max.400kHz, address 7bit)
, C ) incorporated
G D
RS5C372A/B
NO.EA-044-100928
1