3-WIRE SERIAL INTERFACE REAL-TIME CLOCK IC
WITH VOLTAGE MONITORING FUNCTION
RV5C339A
NO.EA-055-0208
OUTLINE
The RV5C339A is a CMOS real-time clock IC 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. This model incorporates 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. 0.35µA 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 (Nch. open drain) 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. This model
comes in an ultra-compact 10-pin SSOP-G (with a height of 1.20mm and a pin pitch of 0.5mm).
FEATURES
• Timekeeping supply voltage ranging from 1.45 to 5.5 volts
• Low supply current: TYP. 0.35µA (MAX. 0.8µA) at 3 volts (at 25˚C)
• Only three signal lines (SCLK, SIO, and CE) required for connection to the CPU.
Maximum clock frequency of 2 MHz (with V
DD
of 5 volts)
• 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 (Nch. open drain output)
Designed to disable 32-kHz clock output in response to a command from the host computer.
• 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 (C
G
and C
D
)
• High precision oscillation adjustment circuit
• CMOS process
1
RV5C339A
BLOCK DIAGRAM
32KOUT
32kHz
OUTPUT
CONTROL
COMPARATOR_W
ALARM_W REGISTER
(MIN,HOUR,WEEK)
VDD
COMPARATOR_D
OSCIN
OSC
OSCOUT
ALARM_D REGISTER
(MIN,HOUR)
VOLTAGE
DETECT
VSS
DIVIDER
CORREC
-TION
DIV
TIME COUNTER
(SEC,MIN,HOUR,WEEK,DAY,MONTH,YEAR)
OSC
DETECT
INTRA
ADDRESS
DECODER
ADDRESS
REGISTER
I/O
CONTROL
SCLK
SIO
INTRB
INTERRUPT CONTROL
SHIFT REGISTER
CE
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)
PIN CONFIGURATION
• 10-pin SSOP-G
32KOUT
SCLK
SIO
INTRB
VSS
1
2
3
4
5
10
9
8
7
6
VDD
OSCIN
OSCOUT
CE
INTRA
2
RV5C339A
PIN DESCRIPTIONS
Pin No. Symbol
Name
Description
The CE pin is used for interfacing with the CPU. Should be held high to allow
7
CE
Chip Enable Input
access to the CPU. Incorporates a pull-down resistor. Should be held low or open
when the CPU is powered off. Allows a maximum input voltage of 5.5 volts regard-
less of supply voltage.
The SCLK pin is used to input clock pulses synchronizing the input and output of
2
SCLK
Serial Clock Input
data to and from the SIO pin. Allows a maximum input voltage of 5.5 volts regard-
less of supply voltage.
3
SIO
Serial Input/Output
The SIO pin is used to input and output data intended for writing and reading in
synchronization with the SCLK pin. CMOS input/output.
The INTRA pin is used to output periodic interrupt signals to the CPU and alarm
6
INTRA
Interrupt Output A
interrupt signals (Alarm_D). Disabled at power-on from 0 volts.
Nch. open drain output.
4
INTRB
Interrupt Output B
The INTRB pin is used to output alarm interrupt signals (Alarm_W). Disable at
power-on from 0 volts. Nch. open drain output.
The 32KOUT pin is used to output 32.768-kHz clock pulses. Enabled at power-on
1
32KOUT 32-kHz Clock Output
from 0 volts. Nch. open drain output. The RV5C339A is designed to be disabled
32-kHz clock output in response to a command from the host computer.
9
8
10
5
OSCIN
OSCOUT
VDD
VSS
Oscillation Circuit
Input/Output
Positive Power Supply Input
Negative Power Supply Input
The OSCIN and OSCOUT pins are used to connect the 32.768-kHz crystal oscilla-
tor (with all other oscillation circuit components built into the RV5C339A.)
The VDD pin is connected to the power supply. The VSS pin is grounded.
3
RV5C339A
ABSOLUTE MAXIMUM RATINGS
Symbol
Item
Conditions
Ratings
(Vss=0V)
Unit
V
DD
V
I
Supply Voltage
Input Voltage 1
Input Voltage 2
Output Voltage 1
SIO
SCLK, CE
SIO
32KOUT, INTRA, INTRB
Topt=25˚C
–0.3 to +6.5
–0.3 to V
DD
+0.3
V
V
–0.3 to +6.5
–0.3 to V
DD
+0.3
V
–0.3 to +6.5
300
–40 to +85
–55 to +125
mW
˚C
˚C
V
O
Output Voltage 2
P
D
Topt
Tstg
Power Dissipation
Operating Temperature
Storage Temperature
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.
RECOMMENDED OPERATING CONDITIONS
Symbol
Item
Conditions
MIN.
(Vss=0V,Topt=–40 to +85˚C)
TYP.
MAX.
Unit
V
DD
V
CLK
Supply Voltage
Timekeeping Voltage
Oscillation Frequency
Pull-up Voltage
32KOUT, INTRA, INTRB
2.0
1.45
32.768
5.5
5.5
V
V
kHz
f
XT
V
PUP
5.5
V
4
RV5C339A
DC ELECTRICAL CHARACTERISTICS
Unless otherwise specified : Vss=0V,V
DD
=3V,Topt=–40 to +85˚C
Symbol
Item
Pin name
Conditions
MIN.
TYP.
MAX.
Unit
V
IH1
V
IH2
V
IL
I
OH
I
OL1
I
OL2
I
IL
R
DNCE
I
OZ1
“H” Input Voltage
“H” Input Voltage
“L” Input Voltage
“H” Output Current
SCLK,CE
SIO
SCLK,CE,SIO
SIO
32KOUT
,
V
OH
=V
DD
–0.5V
V
OL
=0.4V
V
OL
=0.4V
V
I
=5.5V or Vss
V
DD
=5.5V
V
DD
=2.0 to 5.5V
0.8V
DD
0.8V
DD
–0.3
5.5
V
DD
+0.3
0.2V
DD
–0.5
mA
V
”L” Output Current
INTRA, INTRB
SIO
2
0.5
–1
40
120
1
400
1
mA
Input Leakage Current
Pull-down Resistance
SCLK
CE
SIO
µA
kΩ
Vo=5.5V or Vss
V
DD
=5.5V
V
O
=5.5V
V
DD
=3V,CE=OPEN
–1
Output Off-state
Leakage Current
I
OZ2
µA
–1
1
32KOUT,
INTRA, INTRB
I
DD1
Standby Current
V
DD
Output=OPEN
32KOUT=Off mode*
1
0.35
0.8
µA
V
DETH
Supply Voltage Monitoring
Voltage (“H”)
Supply Voltage Monitoring
Voltage (“L”)
Internal Oscillation Capacitance 1
Internal Oscillation Capacitance 2
V
DD
Topt=–30 to +70˚C
1.90
2.10
2.30
V
V
DETL
C
G
C
D
V
DD
OSCIN
OSCOUT
Topt=–30 to +70˚C
1.45
1.60
12
12
1.80
V
pF
*
1) For standby current for outputting 32.768-kHz clock pulses from the 32KOUT pin, see “USAGES, 7. Typical Characteristics”.
5
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