Rev.1.0
_01
3-WIRE REAL-TIME CLOCK
S-35190A
The S-35190A is a low-current-consumption 3-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
3-wire (micro wire) 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
Applications
•
•
•
•
•
•
•
•
Digital still cameras
Digital video cameras
Electronic voltmeters
DVD recorders
TVs, VCRs
PHS
Mobile phones
Car navigation
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
Seiko Instruments Inc.
1
3-WIRE REAL-TIME CLOCK
S-35190A
Rev.1.0
_01
Pin Assignment
8-Pin SOP (JEDEC)
Top view
INT
XOUT
XIN
VSS
1
2
3
4
8
7
6
5
VDD
SIO
SCK
CS
S-35190A-J8T1
Figure 1
8-Pin TSSOP
Top view
INT
XOUT
XIN
VSS
1
2
3
4
8
7
6
5
VDD
SIO
SCK
CS
S-35190A-T8T1
Figure 2
SNT-8A
Top view
INT
XOUT
XIN
VSS
1
2
3
4
8
7
6
5
VDD
SIO
SCK
CS
S-35190A-I8T1G
Figure 3
2
Seiko Instruments Inc.
Rev.1.0
_01
3-WIRE REAL-TIME CLOCK
S-35190A
Description of Pins
Pin No.
Symbol
Table 1
Description
Interrrupt 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)
Chip select input pin
During “H”: The SIO pin allows data I/O.
The SCK pin allows data input.
During “L”: The SIO pin is in the Hi-Z state.
The SCK pin is in the input-disabled
state.
Serial clock input pin
Data I/O from the SIO pin is performed in
synchronization with this clock. However, clock
input is not accepted while the CS pin is “L.”
Serial data I/O pin
It is normally in the Hi-Z state while the CS pin is
“L.” When the CS pin changes from “L” to “H,” the
SIO pin is set to an input pin. It will then be set to
an input or output pin, depending on the
subsequently input command.
Positive power supply pin
1
INT
XOUT
XIN
VSS
Configuration
Nch open-drain output (no
protective diode on the side
of VDD)
2
3
4
CMOS input (built-in pull-
down resistance. No
protective diode on the side
of VDD)
5
CS
6
SCK
CMOS input (no protective
diode on the side of VDD)
7
SIO
Nch open-drain output (no
protective diode on the side
of VDD)
CMOS input
8
VDD
Seiko Instruments Inc.
3
3-WIRE REAL-TIME CLOCK
S-35190A
Rev.1.0
_01
Block Diagram
XIN
XOUT
Oscillator
Division, timing
generator
INT1 register_1
INT1 controller
Clock adjustment register
Comparator 1
Realtime data register
Day of
week
INT
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
SIO
VSS
Shift register
Serial interface
CS
SCK
Figure 4
4
Seiko Instruments Inc.
Rev.1.0
_01
3-WIRE REAL-TIME CLOCK
S-35190A
Absolute Maximum Ratings
Parameter
Power supply voltage
Input voltage
Output voltage
Operating temperature
Storage temperature
Symbol
V
DD
V
IN
V
OUT
T
opr
T
stg
Table 2
Applicable Pin
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
SCK, SIO, CS
SIO, INT
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
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
Table 3
Symbol
Conditions
Min.
1.3
−
40
Typ.
3.0
+
25
Max.
5.5
+
85
Unit
V
°
C
V
DD
T
opr
V
DDT
V
DH
V
DDTm
C
L
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
V
DDTm
V
DDTm
0.5
*1
5.5
5.5
1.1
7.0
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
δ
IC
δ
V
Within 10 seconds
V
DD
=
3.0 V
1.1
−
10
−
3
5.5
1
+
10
+
3
V
s
ppm
ppm/V
pF
pF
V
DD
=
1.3 to 5.5 V
Applied to XIN pin
Applied to XOUT pin
C
g
C
d
0
9.1
8
Seiko Instruments Inc.
5
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