RICOH RS5C313 Datasheet
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 discontinuation 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.
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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 components in standard applications (office equipment, computer equipment, measuring instruments, consumer electronic 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 misoperation 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 support 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 products or the technical information.
June 1995
OUTLINE
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1
FEATURES
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1
BLOCK DIAGRAM
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2
APPLICATIONS
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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
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7
2) Registers
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8
3) Counters
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12
USAGES
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14
1) Read Data
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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
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20
9)
Typical Application
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21
10)
Typical Characteristic Measurements
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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. 0.7µA 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 requiring 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. 0.7µA (MAX. of 1.5µA) at 3V
• Connection to the CPU via only three pins: CE, SCLK, and SIO (for addressing and data read and write operations)
• 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 equipment)
• 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
RS5C313
3
PIN DESCRIPTIONS
Pin No.
Symbol Name Description
1 CE
Chip enable input
The CE pin is used to interface with the CPU and is accessible when held at the high
level. This pin incorporates a pull-down resistor. It should be switched to the low level or opened when not accessed or when powering off the system. Holding the CE
pin at the high level for more than 2.5 seconds forces 1Hz interrupt pulses to be output from the INTR pin for oscillation frequency measurement .
(No pulse is output for less than 1.5 seconds.)
2 SCLK Shift clock input The SCLK pin is used to input shift clock pulses to synchronize data input to, and
output from, the SIO pin.
3 SIO Serial input The SIO pin inputs and outputs written or read data in synchronization with and out-
put shift clock pulses from the SCLK pin. The SIO pin causes high impedance when
the CE pin is held at the low level. After the CE pin is switched to the high level and
the control bits and the address bits are input from the SIO, the SIO pin performs
serial input and output operations
5 INTR Interrupt output The INTR pin outputs cyclic interrupt pulses to the CPU. This pin functions as an
Nch open drain output even when the CE pin is held at the low level.
7 OSCIN
Oscillation circuit
These pins configure an oscillation circuit by connecting a 32.768 kHz crystal
6
OSCOUT
input and output
oscillator between the OSCIN and OSCOUT pins and by connecting a capacitor
between the OSCIN and V
SS pins.
(Any other oscillation circuit components are built into the RS5C313.)
8 V
DD Positive power
supply input The VDD pin is connected to a power supply and the V
SS pin is connected to the
4 V
SS Negative power ground.
supply input
and output
RS5C313
4
Symbol Item Conditions Ratings Unit
VDD Supply voltage –0.3 to +7.0 V
VI Input voltage –0.3 to +VDD+0.3 V
VO1 Output voltage1 SIO –0.3 to +VDD+0.3 V
VO2 Output voltage2 INTR –0.3 to +12 V
PD Maximum power consumption Topt=25˚C 300 mW
Topt Ambient operating temperature –30 to +80 ˚C
Tstg Storage temperature –40 to +125 ˚C
ABSOLUTE MAXIMUM RATINGS
(VSS=0V)
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum ratings are threshold limit values that must not be exceeded even for an instant under
any conditions. Moreover, such values for any two items must not be reached simultaneously. Operation
above these absolute maximum ratings may cause degradation or permanent damage to the device. These
are stress ratings only and do not necessarily imply functional operation below these limits.
RS5C313
5
Symbol Item Pin name Conditions MIN. TYP. MAX. Unit
VIH “H” input voltage CE, SCLK, SIO 0.8VDD VDD V
VIL “L” input voltage CE, SCLK, SIO 0 0.2VDD V
IOH “H” output current SIO VOH=VDD–0.5V –1 mA
I
OL1
“L”
output current
SIO V
OL1=0.5V 1
IOL2 INTR VOL2=0.4V 2
RDN Pull-down resistance CE 45 130 450 kΩ
IILK Input leakage current SCLK VI =VDD or VSS –1 1 µA
I
OZ1
Output off-state
SIO V
O=VDD or VSS –2 2
IOZ2
leakage current
INTR V
O=10V –5 5
V
DD=3V
I/O=OPEN
V
DD=5.5V
I/O=OPEN
C
D
Internal oscillator
OSCOUT 10 pF
capacitance
DC CHARACTERISTICS
Unless otherwise specified:VSS=0V, VDD=5V±10%, Topt=–30 to +80˚C, oscillation frequency=32.768kHz (CL=6pF, R1=30kΩ), CG=10pF
IDD1 Power consumption 1 VDD 0.7 1.5 µA
I
DD2 Power consumption 2 VDD 2 µA
mA
µA
Symbol Item Conditions MIN. TYP. MAX. Unit
VDD Operating supply voltage 2.7 5.0 6.0 V
VCLK Time Keeping supply voltage 1.6 6.0 V
fXT Oscillation frequency 32.768 kHz
CG External oscillator capacitance CL value of crystal=6 to 8pF 5 10 24 pF
V
PUP Applied voltage at OFF INTR 10 V
RECOMMENDED OPERATING CONDITIONS
(VSS=0V, Topt=–30 to +80˚C)
Symbol Item
VDD=5V±10% VDD=3V±10% VDD=5V±20%
Unit
MIN. MAX. MIN. MAX. MIN. MAX.
tCES CE set-up time 175 300 200 ns
tCEH CE hold time 175 300 200 ns
tCR CE recovery time 350 600 400 ns
tSCK SCLK clock cycle 350 600 400 ns
tCKH SCLK “H” clock time 175 300 200 ns
tCKL SCLK “L” clock time 175 300 200 ns
tCKS SCLK clock set-up time 60 100 80 ns
tRE Data output start time (from of SCLK) 120 200 135 ns
tRR Data output delay time (from of SCLK) 120 200 135 ns
tRZ Output floating time 120 200 135 ns
tDS Input data set-up time 50 80 60 ns
tDH Input data hold time 50 50 50 ns
RS5C313
6
AC CHARACTERISTICS
(VSS=0V, Topt=–30 to +80˚C, CL=50pF)
TIMING CHART
Input/output conditions
V
IH = 0.8 × VDD
VIL = 0.2 × VDD
VOH = 0.8 × VDD
VOL = 0.2 × VDD
tSCK
tCES
tCKS
tCEH
tCR
tRE
tRZ
tCKH tCKL
tRR
Read Data
Write Data
t
DS tDH
CE
SCLK
SIORead cycle
Write cycle
SIO
*
) The ability that is fair in “H” or “L” slanted line department
Address
A3
A2 A1 A0
RS5C313
7
0 0 0 0 0 1-second counter S8 S4 S2 S1
1 0 0 0 1 10-second counter S40 S20 S10
2 0 0 1 0 1-minute counter M8 M4 M2 M1
3 0 0 1 1 10-minute counter — M40 M20 M10
4 0 1 0 0 1-hour counter H8 H4 H2 H1
5 0 1 0 1 10-hour counter — —
P/A or H
20 H10
6 0 1 1 0 Day-of-the-week counter — W4 W2 W1
7 0 1 1 1 Interrupt cycle register CT3 CT2 CT1 CT0
8 1 0 0 0 1-day counter D8 D4 D2 D1
9 1 0 0 1 10-day counter — — D20 D10
A 1 0 1 0 1-month counter MO8 MO4 MO2 MO1
B 1 0 1 1 10-month counter — — — MO10
C 1 1 0 0 1-year counter Y8 Y4 Y2 Y1
D 1 1 0 1 10-year counter Y80 Y40 Y20 Y10
E 1 1 1 0 Control register CTFG 12/24
WTEN/XSTP
*3 ADJ/BSY
*
4
F 1 1 1 1 Test register — — — TEST
D3
D2 D1 D0
Data*
1
*
1) All the listed data can be read and written .
*
2) The “—” mark indicates data which can be read only and set to “0” when read .
*
3) The WTEN/XSTP bit of the control register is set to WTEN for write operation and XSTP for read operation.
*
4) The ADJ/BSY bit of the control register is set to ADJ for write operation and BSY for read operation.
Description
1.
Addressing
FUNCTIONAL DESCRIPTIONS
—*
2
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