Rev.1.2
_00
2-WIRE REAL-TIME CLOCK
S-35390A
The S-35390A is a low-current-consumption 2-wire CMOS real-time clock IC
that features a wide operating voltage range (1.3 V to 5.5 V) and can be
driven on a variety of supply voltages, from a main supply to a backup
supply. The time keeping current consumption of 0.25
µA
and minimum
time keeping operation voltage of 1.1 V enable greatly increased battery
duration.
In a system that operates on a backup battery, the free register incorporated
in the real-time clock can be used for the user backup memory function.
The user register can hold data on a supply voltage as low as 1.2 V (min.),
so the data stored in the register before the main power supply was cut can
be called any time after the voltage is restored.
This product also includes a clock adjustment function that enables wide-
ranging correction of deviation in the frequency of the crystal oscillator at a
minimum resolution of 1 ppm. Also, by combining this function with a
temperature sensor, the clock adjustment value can be set in accordance
with changes in the temperature, which makes it possible to realize a clock
function that retains a high degree of accuracy regardless of temperature
variation.
Features
•
•
•
•
•
•
•
•
•
•
•
•
Low current consumption:
0.25
µA
typ. (V
DD
=
3.0 V, Ta
=
25°C)
Wide operating voltage range:
1.3 to 5.5 V
Minimum time keeping operation voltage: 1.1 V
Built-in clock adjustment function
Built-in free user register
2-wire (I
2
C-BUS)
*1
CPU interface
Built-in alarm interrupter
Built-in flag generator at power down or power on
Auto calendar up to the year 2099, automatic leap year calculation function
Built-in constant voltage circuit
Built-in 32 kHz crystal oscillator circuit (C
d
built in, C
g
external)
Package: 8-pin SOP (JEDEC), 8-pin TSSOP, SNT-8A
*1.
I
2
C-BUS is a trademark of Philips Electronics N.V.
Applications
•
•
•
•
•
•
•
•
Digital still cameras
Digital video cameras
Electronic power meters
DVD recorders
TVs, VCRs
PHS
Mobile phones
Car navigation
Seiko Instruments Inc.
1
2-WIRE REAL-TIME CLOCK
S-35390A
Rev.1.2
_00
Packages
Package Name
8-Pin SOP(JEDEC)
8-Pin TSSOP
SNT-8A
Package
FJ008-A
FT008-A
PH008-A
Drawing Code
Tape
FJ008-D
FT008-E
PH008-A
Reel
FJ008-D
FT008-E
PH008-A
Pin Assignment
8-Pin SOP(JEDEC)
Top view
INT1
XOUT
XIN
VSS
1
2
3
4
8
7
6
5
VDD
SDA
SCL
INT2
S-35390A-J8T1
Figure 1
8-Pin TSSOP
Top view
INT1
XOUT
XIN
VSS
1
2
3
4
8
7
6
5
VDD
SDA
SCL
INT2
S-35390A-T8T1
Figure 2
SNT-8A
Top view
INT1
XOUT
XIN
VSS
1
2
3
4
8
7
6
5
VDD
SDA
SCL
INT2
S-35390A-I8T1G
Figure 3
2
Seiko Instruments Inc.
Rev.1.2
_00
2-WIRE REAL-TIME CLOCK
S-35390A
Description of Pins
Table 1
Pin No.
Symbol
Description
Interrupt 1 signal output pin
Depending on the mode set by INT1 register_1
and the status register, it outputs low or a clock
when the time is reached. It is disabled by
rewriting the status register.
Crystal oscillator connect pin (32,768 Hz)
(C
d
built in, C
g
external)
Negative power supply pin (GND)
Interrrupt 2 signal output pin
Depending on the mode set by INT1 register_2
and the status register, it outputs low or clock
when time is reached. It is disabled by rewriting
the status register.
Serial clock input pin
Since signal processing is done on the SCL
signal rising/falling edge, give great care to the
rising/falling time and comply strictly with the
specifications.
Serial data I/O pin
Normally, it is pulled up to the V
DD
voltage by a
resistor and connected with another open-drain
output or open-collector output device via a
wired-OR connection.
Positive power supply pin
Configuration
Nch open-drain output (no
protective diode on the side
of VDD)
Nch open-drain output (no
protective diode on the side
of VDD)
1
INT1
XOUT
XIN
VSS
2
3
4
5
INT2
CMOS input (no protective
diode on the side of VDD)
6
SCL
7
SDA
Nch open-drain output (no
protective diode on the side
of VDD)
CMOS input
8
VDD
Seiko Instruments Inc.
3
2-WIRE REAL-TIME CLOCK
S-35390A
Rev.1.2
_00
Block Diagram
XIN
XOUT
Oscillator
Division, timing
generator
INT1 register_1
INT1 controller
INT1
Clock adjustment register
Comparator 1
Realtime data register
Day of
week
Status register_1
Status register_2
VDD
Power supply
voltage
detector
Constant
voltage circuit
Second Minute
Hour
Day
Month
Year
Comparator 2
INT1 register_2
INT2 controller
INT2
SDA
VSS
Shift register
Serial interface
SCL
Figure 4
4
Seiko Instruments Inc.
Rev.1.2
_00
2-WIRE REAL-TIME CLOCK
S-35390A
Absolute Maximum Ratings
Table 2
Parameter
Power supply voltage
Input voltage
Output voltage
Operating temperature
Storage temperature
Symbol
V
DD
V
IN
V
OUT
T
opr
T
stg
Applicable Pin
SCL, SDA
SDA,
INT1
,
INT2
Rating
V
SS
−
0.3 to V
SS
+
6.5
V
SS
−
0.3 to V
SS
+
6.5
V
SS
−
0.3 to V
SS
+
6.5
−40
to
+85
−55
to
+125
Unit
V
V
V
°C
°C
Caution The absolute maximum ratings are rated values exceeding which the product
could suffer physical damage. These values must therefore not be exceeded
under any conditions.
Recommended Operating Conditions
Table 3
Parameter
Power supply voltage
Operating temperature
Time keeping voltage range
Register hold voltage
Minimum time keeping voltage range
Crystal oscillator C
L
value
*1.
Reference value
Symbol
V
DD
T
opr
V
DDT
V
DH
V
DDTm
C
L
Conditions
Ta
= −40
to
+85°C
V
DD
=
1.3 to 5.5 V
Ta
= −40
to
+85°C
Ta
= −40
to
+85°C
Ta
= −40
to
+85°C
Min.
1.3
−40
V
DDTm
V
DDTm
0.5
*1
Typ.
3.0
+25
Max.
5.5
+85
5.5
5.5
1.1
7.0
Unit
V
°C
V
V
V
pF
Oscillation Characteristics
Table 4
(Ta
=
25°C, V
DD
=
3.0 V, DS-VT-200 crystal oscillator (C
L
=
6 pF, 32,768 Hz) manufactured by Seiko Instruments Inc.)
Parameter
Symbol
Conditions
Min.
Typ.
Max.
Unit
Oscillation start voltage
Oscillation start time
IC-to-IC frequency deviation
*1
Frequency voltage deviation
Internal oscillation capacitance (1)
Internal oscillation capacitance (2)
*1.
Reference value
V
STA
t
STA
δIC
δV
C
g
C
d
Within 10 seconds
V
DD
=
3.0 V
V
DD
=
1.3 to 5.5 V
Applied to XIN pin
Applied to XOUT pin
1.1
−10
−3
0
8
5.5
1
+10
+3
9.1
V
s
ppm
ppm/V
pF
pF
Seiko Instruments Inc.
5
FPGA/CPLD
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