ELECTRONIC DEVICES DIVISION
ULTRA-COMPACT
REAL-TIME CLOCK IC
RS5C313
APPLICATION MANUAL
NO.EA-034-9908
NOTICE
1. The products and the product specifications described in this application manual are subject to change or dis-
continuation of production without notice for reasons such as improvement. Therefore, before deciding to use
the products, please refer to Ricoh sales representatives for the latest information thereon.
2. This application manual may not be copied or otherwise reproduced in whole or in part without prior written con-
sent of Ricoh.
3. Please be sure to take any necessary formalities under relevant laws or regulations before exporting or other-
wise taking out of your country the products or the technical information described herein.
4. The technical information described in this application manual shows typical characteristics of and example
application circuits for the products. The release of such information is not to be construed as a warranty of or a
grant of license under Ricoh's or any third party's intellectual property rights or any other rights.
5. The products listed in this application manual are intended and designed for use as general electronic compo-
nents in standard applications (office equipment, computer equipment, measuring instruments, consumer elec-
tronic products, amusement equipment etc.). Those customers intending to use a product in an application
requiring extreme quality and reliability, for example, in a highly specific application where the failure or misoper-
ation of the product could result in human injury or death (aircraft, spacevehicle, nuclear reactor control system,
traffic control system, automotive and transportation equipment, combustion equipment, safety devices, life sup-
port system etc.) should first contact us.
6. We are making our continuous effort to improve the quality and reliability of our products, but semiconductor
products are likely to fail with certain probability. In order prevent any injury to persons or damages to property
resulting from such failure, customers should be careful enough to incorporate safety measures in their design,
such as redundancy feature, fire-containment feature and fail-safe feature. We do not assume any liability or
responsibility for any loss or damage arising from misuse or inappropriate use of the products.
7. Anti-radiation design is not implemented in the products described in this application manual.
8. Please contact Ricoh sales representatives should you have any questions or comments concerning the prod-
ucts or the technical information.
June 1995
OUTLINE
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1
FEATURES
....................................................................................................
1
BLOCK DIAGRAM
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2
APPLICATIONS
.............................................................................................
2
PIN CONFIGURATION
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2
PIN DESCRIPTIONS
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3
ABSOLUTE MAXIMUM RATINGS
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4
RECOMMENDED OPERATING CONDITIONS
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5
DC CHARACTERISTICS
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5
AC CHARACTERISTICS
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6
TIMING CHART
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6
FUNCTIONAL DESCRIPTIONS
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7
1)
Addressing
...............................................................................................
7
2) Registers
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8
3) Counters
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12
USAGES
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14
1) Read Data
..............................................................................................
14
2) Write Data
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15
3) CE Pin
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16
4) Configuration of Oscillating Circuit
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17
5) Oscillator Halt Sensing
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18
6) Typical Power Supply Circuit
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18
7) Oscillation Frequency Adjustment
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19
8) Interrupt Operation
....................................................................................
20
9) Typical Application
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21
10) Typical Characteristic Measurements
...............................................................
22
11) Typical Software-based Operations
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24
PACKAGE DIMENSIONS
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28
PACKAGE SPECIFICATION
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28
RS5C313
APPLICATION MANUAL
CONTENTS
ULTRA-COMPACT
REAL-TIME CLOCK IC
RS5C313
1
OUTLINE
The RS5C313 is a CMOS type real-time clock which is connected to the CPU via three signal lines and capable of
serial transmission of clock and calendar data to the CPU. The RS5C313 can generate various interrupt clock pulses
lasting for long periods (one month). Driving an oscillation circuit at constant voltage, the circuit undergoes few
voltage fluctuations and consequently realizes low current consumption (TYP. 0.7 A at 3 V). It also provides an
oscillator halt sensing function for application to data validity at power-on and other occasions. Integrated into an
ultra-compact and ultra-thin 8pin SSOP (0.65mm pitch), the RS5C313 is the optimum choice for equipment requir-
ing small size and low power consumption.
There is RS5C314 reversing the logic of serial clock for series goods.
Time Keeping Supply Voltage: 1.6 to 6.0 V
Operating Supply Voltage: 2.7 to 6.0 V
Low Current Consumption: TYP. 0.7A (MAX. of 1.5A) at 3V
Connection to the CPU via only three pins: CE, SCLK, and SIO (for addressing and data read and write opera-
tions)
A clock counter (counting hours, minutes, and seconds) and a calendar counter (counting leap years, years,
months, days, and days of the week) in binary-coded decimal (BCD) code
Generation of interrupt pulses to the CPU with cycles ranging from 1 month to 1/1024 Hz, interrupt flags, and
interrupt halt
Software-based alarming through clock-interlocked interrupt operation
Oscillator halt sensing to judge internal data validity
Second digit adjustment by 30 seconds
12-hour or 24-hour time display selectable
Automatic leap year recognition up to the year 2099
CMOS logic
Package: 8pin SSOP (0.65mm pitch)
FEATURES
RS5C313
2
APPLICATIONS
Communication equipment (Multi-function telephone, portable telephone, PHS, Pager)
Office automation (Facsimile, portable facsimile)
Personal computer (Desk top type, notebook type, word proccesor, PDA, electronic notebook, TV games)
Audio visual equipment (Portable audio equipment, video camera, camera, digital camera, remote control equip-
ment)
Home use (Rice cooker, microwave range)
PIN CONFIGURATION
1
2
3
4
CE
SCLK
SIO
VSS
8
7
6
5
VDD
OSCIN
OSCOUT
INTR
8pin SSOP
BLOCK DIAGRAM
SEC.
MIN.
HOUR WEEK
DAY
MONTH YEAR
OSCIN
OSCOUT
VDD
VSS
INTR
OSC
DIV
OSC
DETECT
VOLTAGE
REGULATOR
ADDRESS
DECODER
INTERRUPT
CONTROL
SHIFT REGISTER
I/O
CONTROL
ADDRESS
REGISTER
SIO
SCLK
CE
TIME COUNTER
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