Document Outline
- S-3513B
- Cover
- Features
- Applications
- Package
- Block Diagram
- Product Code Structure
- Pin Assignment
- Description of Pins
- Absolute Maximum Ratings
- Recommended Operating Conditions
- Oscillation Characteristics
- DC Electrical Characteristics
- AC Electrical Characteristics
- Timing Charts
- Description of Operation
- Samples of Application Circuits
- Adjustment of Oscillating Frequency
- Precautions
- Characteristics (Reference Data)
- Package Drawing
Rev. 1.2
_00
REAL-TIME CLOCK
S-3513B
Seiko Instruments Inc.
1
S-3513B is a CMOS real-time clock IC, which is designed
to transfer or set each data of a clock and calender as
requested by a CPU. This IC is connected to the CPU by
three signal buses. It has a 32 kHz output pin and can
supply signals to another IC. Because the oscillating
circuit of the S-3513B is driven at constant voltage, the IC
operates with low power consumption.
Features
Low power consumption:
0.7
A typ. (V
DD
=3.0 V)
Wide area of operating voltage: 1.7 to 5.5 V
BCD input/output of year, month, day, day of a week, hour, minute and second
CPU interface via three wires
Auto calender till the year of 2,099
(automatic leap year arithmetic feature included)
Built-in power voltage detecting circuit
Built-in constant voltage circuit
Built-in flag generating circuit on power on/off
Uninterrupted 32 kHz clock signal output
Built-in 32 kHz crystal oscillating circuit (internal Cd, external Cg)
Applications
Cellular phone
PHS
A variety of pagers
TV set and VCR
Camera
Package
8-pin SSOP (pin pitch : 0.65 mm) (Package drawing code : FS008-A)
REAL-TIME CLOCK
S-3513B
Rev.1.2
_00
2
Seiko Instruments Inc.
Block Diagram
Figure 1
Status register
Oscillating
circuit
SCK
CS
Timing
generation
Power
voltage
detecting
circuit
Constant
voltage
circuit
VDD
VSS
Second
Minute
Hour
Day of
week
Day
Month
Year
Shift register
Serial
Interface
XIN
XOUT
SIO
F32K
REAL-TIME
CLOCK
Rev.1.2
_00
S-3513B
Seiko Instruments Inc.
3
Product Code Structure
S-3513BE
FS
Package name (abbreviation)
FS: 8-Pin SSOP
Description (fixed)
Pin Assignment
8-pin SSOP
Top view
XOUT
VSS
6
5
8
7
3
4
1
2
SIO
VDD
SCK
CS
F32K
XIN
Figure 2
Description of Pins
Table 1
Pin No.
Symbol
Description
Configuration
1
F32K
32,768 kHz clock signal output pin
Because these signals are output with no
interruption, no command can control these
signals.
Nch open drain output
(No protective diode on the
side of VDD)
2
XIN
Crystal oscillator connect pin (32,768 Hz)
-
3
XOUT
(Internal Cd, External Cg)
-
4
VSS
Negative power supply pin (GND)
-
5 CS
Chip select input pin.
During "H" : The SIO pin allows data
input/output.
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.
CMOS input (Included
pull-down resistance.
No protective diode on the
side of VDD)
6
SCK
Serial clock input pin.
The input/output of data from the SIO pin is
performed in synchronization with this clock.
However, the clock is not accepted while the
CS pin is "L."
CMOS input (No protective
diode on the side of VDD)
7 SIO
Serial data input/output 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 be
set to an input or output pin, depending on an
subsequently input command.
Nch open drain output
(No protective diode on the
side of VDD)
CMOS input
8
VDD
Positive power supply pin.
-
REAL-TIME CLOCK
S-3513B
Rev.1.2
_00
4
Seiko Instruments Inc.
Absolute Maximum Ratings
Table 2
Item
Symbol
Applicable pin, conditions
Rating
Unit
Power voltage
V
DD
-
V
SS
-0.3 to V
SS
+6.5 V
Input voltage
V
IN
Applied to SCK, SIO
V
SS
-0.3 to V
SS
+6.5 V
Output voltage
V
OUT
Applied to SIO, F32K
V
SS
-0.3 to V
SS
+6.5 V
Operating temperature
T
opr
V
DD
=3.0 V
-40 to +85
C
Storage temperature
T
stg
-
-55 to +125
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
Item
Symbol
Condition Min.
Typ.
Max.
Unit
Power voltage
V
DD
- 1.7
3.0
5.5
V
Operating temperature
T
opr
-
-20
+25
+70
C
Oscillation Characteristics
Table 4
(Unless otherwise specified : Ta
=25C, V
DD
=3 V, DS-VT-200 (crystal oscillator, C
L
=6 pF, 32,768 Hz) manufactured by SII Quartz Techno Ltd.)
Item Symbol
Condition
Min.
Typ.
Max.
Unit
Oscillation start voltage
V
STA
Within 10 seconds
1.7
- 5.5 V
Oscillation start time
T
STA
-
-
- 1 s
IC-to-IC frequency diversity
IC
-
-10
-
+10 ppm
Frequency voltage diversity
V V
DD
=1.7 to 5.5 V
-3
-
+3 ppm/V
Input capacity
C
g
Applied to the XIN pin
3
- 35 pF
Output capacity
C
d
Applied to the XOUT pin
- 12 - pF
REAL-TIME
CLOCK
Rev.1.2
_00
S-3513B
Seiko Instruments Inc.
5
DC Electrical Characteristics
Table 5 DC characteristics (3 V)
(Unless otherwise specified : Ta
=25C, V
DD
=3 V, DS-VT-200 (crystal oscillator, C
L
=6 pF, 32,768 Hz) manufactured by SII Quartz Techno Ltd.)
Item Symbol
Applicable
pin Condition Min.
Typ.
Max.
Unit
Operating voltage range
V
DD
-
Ta
= -20 to +70C
1.7 3.0 5.5 V
Current consumption 1
I
DD1
-
During no communications
-
0.7 1.5
A
Current consumption 2
I
DD2
-
During communications
(SCL
=100 kHz)
-
5.5 10
A
Input leak current 1
I
IZH
SCK,
SIO
V
IN
=V
DD
-0.5
-
0.5
A
Input leak current 2
I
IZL
SCK,
SIO
V
IN
=V
SS
-0.5
-
0.5
A
Input current 1
I
IL1
CS
V
IN
=5.5 V
2 6 20
A
Input current 2
I
IL2
CS
V
IN
=0.4 V
40 110 300
A
Output leak current1
I
OZH
F32K,
SIO
V
OUT
=V
DD
-0.5
-
0.5
A
Output leak current2
I
OZL
F32K,
SIO
V
OUT
=V
SS
-0.5
-
0.5
A
Input voltage 1
V
IH
SIO,
SCK,
CS
- 0.8V
DD
-
-
V
Input voltage 2
V
IL
SIO,
SCK,
CS
-
-
- 0.2V
DD
V
Output current 1
I
OL1
F32K
V
OUT
=0.4 V
1.5 2.5
-
mA
Output current 2
I
OL2
SIO
V
OUT
=0.4 V
5 10
-
mA
Power voltage detection
voltage 1
V
DET1
-
Ta
=+25C
1.8 2.0 2.2 V
Power voltage detection
voltage 2
V
DET2
-
Ta
= -20 to +70C
1.72
-
2.3 V
Table 6 DC characteristics (5 V)
(Unless otherwise specified : Ta
=25C, V
DD
=5 V, DS-VT-200 (crystal oscillator, C
L
=6 pF, 32,768 Hz) manufactured by SII Quartz Techno Ltd.)
Item Symbol
Applicable
pin
Condition Min.
Typ.
Max.
Unit
Operating voltage range
V
DD
-
Ta
= -20 to +70C
1.7 3.0 5.5 V
Current consumption 1
I
DD1
-
During no communications
-
1.6 3.0
A
Current consumption 2
I
DD2
-
During communications
(SCL
=100 kHz)
-
12 20
A
Input leak current 1
I
IZH
SCK,
SIO
V
IN
=V
DD
-0.5
-
0.5
A
Input leak current 2
I
IZL
SCK,
SIO
V
IN
=V
SS
-0.5
-
0.5
A
Input current 1
I
IL1
CS
V
IN
=5.5 V
10 25 50
A
Input current 2
I
IL2
CS
V
IN
=0.4 V
100 175 400
A
Output leak current1
I
OZH
F32K,
SIO
V
OUT
=V
DD
-0.5
-
0.5
A
Output leak current2
I
OZL
F32K,
SIO
V
OUT
=V
SS
-0.5
-
0.5
A
Input voltage 1
V
IH
SIO,
SCK,
CS
- 0.8V
DD
-
-
V
Input voltage 2
V
IL
SIO,
SCK,
CS
-
-
- 0.2V
DD
V
Output current 1
I
OL1
F32K
V
OUT
=0.4 V
2.0 3.5
-
mA
Output current 2
I
OL2
SIO
V
OUT
=0.4 V
6 12
-
mA
Power voltage detection
voltage 1
V
DET1
-
Ta
=+25C
1.8 2.0 2.2 V
Power voltage detection
voltage 2
V
DET2
-
Ta
= -20 to +70C
1.72
-
2.3 V
REAL-TIME CLOCK
S-3513B
Rev.1.2
_00
6
Seiko Instruments Inc.
AC Electrical Characteristics
(S-3513B, R
L
=10 K, C
L
=80 pF)
Table 7 AC characteristics 1
Conditions : V
DD
=1.7 V to 5.5 V, Ta= -20 to 70C
Input;
V
IH
=0.8 V
DD
, V
IL
=0.2 V
DD
, Output; V
OH
=0.8 V
CC
, V
OL
=0.2 V
CC
(V
CC
=5.0 V)
Item Symbol
Min.
Typ.
Max.
Unit
Clock pulse width
t
SCK
5
- 250000 s
Setup time before CS rising
t
DS
1
-
-
s
Hold time after CS rising
t
CSH
1
-
-
s
Input data setup time
t
ISU
1
-
-
s
Input data hold time
t
IHO
1
-
-
s
Output data definition time
t
ACC
-
- 3.5 s
Setup time before CS falling
t
CSS
1
-
-
s
Hold time after CS falling
t
DH
1
-
-
s
Input rising/falling time
t
R
, t
F
-
- 0.1 s
Caution Since the output form of the SIO pin is Nch open-drain output, the rising time
of t
ACC
is determined by the values of load resistance (R
L
) and load capacity
(C
L
) outside the IC. Use this as a reference value.
Table 8 AC characteristics 2
Conditions : V
DD
=3.0 0.3 V, Ta= -20 to 70C
Input;
V
IH
=0.8 V
DD
, V
IL
=0.2 V
DD
, Output; V
OH
=0.8 V
CC
, V
OL
=0.2 V
CC
(V
CC
=5.0 V)
Item Symbol
Min.
Typ.
Max.
Unit
Clock pulse width
t
SCK
0.7
- 250000 s
Setup time before CS rising
t
DS
0.2
-
-
s
Hold time after CS rising
t
CSH
0.2
-
-
s
Input data setup time
t
ISU
0.2
-
-
s
Input data hold time
t
IHO
0.2
-
-
s
Output data definition time
t
ACC
-
- 1.0 s
Setup time before CS falling
t
CSS
0.2
-
-
s
Hold time after CS falling
t
DH
0.2
-
-
s
Input rising/falling time
t
R
, t
F
-
- 0.05 s
Caution Since the output form of the SIO pin is Nch open-drain output, the rising time
of t
ACC
is determined by the values of load resistance (R
L
) and load capacity
(C
L
) outside the IC. Use this as a reference value.
Table 9 AC characteristics 3
Conditions : V
DD
=5.0 0.5 V, Ta= -20 to 70C
Input;
V
IH
=0.8 V
DD
, V
IL
=0.2 V
DD
, Output; V
OH
=0.8 V
CC
, V
OL
=0.2 V
CC
(V
CC
=5.0 V)
Item Symbol
Min.
Typ.
Max.
Unit
Clock pulse width
t
SCK
0.5
- 250000 s
Setup time before CS rising
t
DS
0.1
-
-
s
Hold time after CS rising
t
CSH
0.1
-
-
s
Input data setup time
t
ISU
0.1
-
-
s
Input data hold time
t
IHO
0.1
-
-
s
Output data definition time
t
ACC
-
- 0.3 s
Setup time before CS falling
t
CSS
0.1
-
-
s
Hold time after CS falling
t
DH
0.1
-
-
s
Input rising/falling time
t
R
, t
F
-
- 0.05 s
Caution Since the output form of the SIO pin is Nch open-drain output, the rising time
of t
ACC
is determined by the values of load resistance (R
L
) and load capacity
(C
L
) outside the IC. Use this as a reference value.
REAL-TIME
CLOCK
Rev.1.2
_00
S-3513B
Seiko Instruments Inc.
7
Timing
Charts
t
CSH
t
DS
t
DH
t
DH
t
CSS
t
DS
CS
SCK
SIO
Figure 3
Figure 5
80
%
80
%
20
%
20
%
50
%
20
%
80
%
20
%
20
%
80
%
t
ACC
t
SCK
t
SCK
t
R
,t
F
t
F
t
R
t
ISU
SCK
Input data
t
IHO
50
%
SCK
Output data
Figure 4
REAL-TIME CLOCK
S-3513B
Rev.1.2
_00
8
Seiko Instruments Inc.
Description of Operation
1. Serial interface
S-3513B receives various commands via a 3-wire serial interface to read/write data. This section
covers the transfer methods of this product.
1.1 Communication
data configuration
After turning the CS pin to "H", send a 4-bit fixed code "0110" and succeedingly transfer the
command of a 3-bit length and read/write command of a 1-bit length.
Figure 6 Communication data
1.2 Command configuration
There are six types of commands which read from and write to various registers. The table
below lists them. Any command that is not listed in the table provides no operation.
Table 10 Command list
C2 C1 C0
Description
0
0
0
Reset (00 (year), 01 (month), 01 (day), 0 (day of week),
00 (minute), 00 (second))
*1
0 0 1
Status
register
access
0
1
0
Real-time data access 1 (year data to)
0
1
1
Real-time data access 2 (hour data to)
1 1 0
Test
mode
start
*2
1 1 1
Test
mode
end
*2
*1. Don't care the R/W bit of this command.
*2. This command is access-disabled due to specific use for the IC test.
Caution Do not enter a command not listed in the above table.
1.3 Data
reading
When you input data from the SIO pin in synchronization with the falling of the SCK pin after
turning the CS pin to "H", the data is included into the inside of S-3513B at the eighth rising of the SCK
clock and the state of data reading is reached when the R/W bit has "1". The state leads to output of
data corresponding each command in synchronization with the falling of subsequent SCK clock input.
Remark When the number of SCK clocks is less than eight, the state of clock waiting is reached and
no processing is done.
When SCK clocks are more than required, they are processed in order from the first and the
clocks other than those required are ignored.
Command
0
1
1
0
C2
C1
C0
R/W
Fixed code
MSB
LSB
Read/Write bit
REAL-TIME
CLOCK
Rev.1.2
_00
S-3513B
Seiko Instruments Inc.
9
SCK
SCK
SCK
TEST
64
9
1
1
0
1
0
0
1
1
0
X
Output mode switching
(1) Real-time data reading 1
9
1
(3) Status register reading
Year data
Second data
1
1
0
0
0
1
1
0
X
Output mode switching
Status data
Input mode switching
LSB
MSB
TEST
32
9
1
1
1
1
0
0
1
1
0
X
Output mode switching
(2) Real-time data reading 2
Hour data
Second data
LSB
MSB
LSB
MSB
LSB
MSB
LSB
MSB
Input mode switching
Input mode switching
Command
Command
Command
LSB
MSB
LSB
MSB
LSB
MSB
POWER
SIO
CS
SIO
CS
SIO
CS
Figure 7 Read communication
REAL-TIME CLOCK
S-3513B
Rev.1.2
_00
10
Seiko Instruments Inc.
1.2 Data
writing
When you input data from the SIO pin in synchronization with the falling of the SCK pin after
turning the CS pin to "H", the data is included into the inside of S-3513B at the eighth rising of the SCK
clock and the state of data writing is reached when the R/W bit has "0". In the state, the data is written
to registers according each command in synchronization with the falling of subsequent SCK clock
input.
SCK
SCK
SCK
TEST
64
9
1
0
0
1
0
0
1
1
0
X
(1) Real-time data writing 1
9
1
(3) Status register writing
Year data
Second data
0
1
0
0
0
1
1
0
X
Status data
LSB
MSB
TEST
32
9
1
0
1
1
0
0
1
1
0
X
(2) Real-time data writing 2
Hour data
Second data
LSB
MSB
LSB
MSB
LSB
MSB
LSB
MSB
Command
Command
Command
LSB
MSB
LSB
MSB
LSB
MSB
POWER
SIO
CS
SIO
CS
SIO
CS
Figure 8 Write communication
REAL-TIME
CLOCK
Rev.1.2
_00
S-3513B
Seiko Instruments Inc.
11
2. Register
configuration
2.1
Real-time data register
The real-time data register is a 56-bit register which stores the BCD code of the data of year,
month, day, day of week, hour, minute and second. Any read/write operation performed by the
real-time data access command sends or receives the data from LSB on the first digit of the year data.
AM/
PM
Y80 Y40 Y20 Y10 Y8
Y4
Y2
Y1
MSB
LSB
Year data (00 to 99)
0
0
0
M10 M8
M4
M2
M1
MSB
LSB
Month data (01 to 12)
0
0
D20 D10 D8
D4
D2
D1
MSB
LSB
Day data (01 to 31)
0
0
0
0
0
W4
W2
W1
MSB
LSB
Day of week data (00 to 06)
A septenary counter. Set it so that it
corresponds to the day of the week.
0
H20 H10 H8
H4
H2
H1
MSB
LSB
Hour data (00 to 23 or 00 to 11)
0
MSB
LSB
Minute data (00 to 59)
TEST S40 S20 S10 S8
S4
S2
S1
MSB
LSB
Second data (00 to 59) and test flag
m10 m8
m4
m2
m1
AM/PM : For 12-hour expression, 0:AM and 1:PM.
For 24-hour expression, this flag has no
meaning but either "0" or "1" must be
written.
Sets the lower two digits of the Christian era (00
to 99) and links together with the auto calender
feature till 2,099.
The count value is automatically changed by the
auto calender feature:
1 to 31: 1, 3, 5, 7, 8, 10, 12
1 to 30: 4, 6, 9, 11
1 to 29: 2 (leap year)
1 to 28: 2 (common year)
TEST : Turns to "1" during the test mode.
m20
m40
Figure 9
REAL-TIME CLOCK
S-3513B
Rev.1.2
_00
12
Seiko Instruments Inc.
2.2 Status
register
The status register, which is an 8-bit register, is used to display and set modes. The POWER
flag is dedicated to read operations.
B7
LSB
POWER
12/24
R
R/W
R/W
R/W
R/W
D5
D3
MSB
B6
B5
B4
B3
B2
B1
B0
D1
-
-
-
Figure 10
B7:POWER
This flag turns to "1" if the power voltage detecting circuit operates during
power-on or changes in power voltage (below V
DET
). Once turning to "1," this
flag does not turns back to "0" even when the power voltage reaches or exceeds
the detection voltage. When the flag is "1", you must send the reset command
(or the status register read command), and turn it to "0." It is a read-only flag.
B6:12/24
This flag is used to set 12-hour or 24-hour expression.
0 : 12-hour expression
1 : 24-hour expression
B5, B3, B1:
These bits can be used as user memory bits. They have no effect on the timer
function.
B4, B2, B0:
These bits are ignored when data has been written to them. When data is read
from them, it is undetermined.
2.3 Test
flag
The test flag is a 1-bit register which is assigned to MSB of the second data of the real-time data
register. If transferred data is considered as the test mode starting command due to the receiving of
the test mode starting command or noises, "1" is set. When "1" is set, you must send the test mode
ending command or reset command.
3. Initialization
Note that S-3513B has different initializing operations, depending on states.
3.1 When power is turned on
When power is turned on, the status register is set to "82h" and the INT register to "8000h." In
other words, "1" is set in bit 7 (POWER flag) of the status register. In normal use, make sure to send
the reset command when turning on the power.
Real-time data register : 00 (year), 01 (month), 01 (day), 0 (day of week), 00 (hour), 00
(minute), 00 (second)
Status register
: "82h"
3.2 When the power voltage detecting circuits operates
The power voltage detecting circuit included in S-3513B operates and sets "1" at the bit 7
(POWER flag) of the internal status register when power is turned on or power voltage is reduced.
Once "1" is set, it is held even after the power voltage gets equal to or higher than the detection
voltage, i.e., power voltage detector threshold. When the flag has "1", you must send the reset
command from CPU and initialize the flag. At this point, other registers does not change.
However, if the POWER flag has "0" during the power-on reset of CPU (S-3513B does not reach any
indefinite area during backup), you do not have to send the reset command.
REAL-TIME
CLOCK
Rev.1.2
_00
S-3513B
Seiko Instruments Inc.
13
3.3 When the reset command is received
When the reset command is received, each register turns as follows:
Real-time data register : 00 (year), 01 (month), 01 (day), 0 (day of week), 00 (hour), 00
(minute), 00 (second)
Status register
: "00h"
0
1 1 0
R
/
W
M
S
B
SIO LINE
0 0 1
L
S
B
1
command
status read command
V
DD
POWER
flag
0 1 1 0
R
/
W
M
S
B
SIO LINE
0 0 1
L
S
B
1
command
V
DD
POWER
flag
0 1 1 0
R
/
W
M
S
B
0 0
L
S
B
1
1 0 0 0 0 0
POWER flag
0
Don't care
backup state (S-3513B does not reach any indefinite area)
0 1 1 0
R
/
W
M
S
B
0 1
L
S
B
0 0 0 0 0 0 0
POWER flag
0
CPU down
reset command
status data
1
1
0
data
0
data
status read command
status data
command
command
real-time data read command
M
S
B
M
S
B
L
S
B
L
S
B
Figure 11 Initializing
REAL-TIME CLOCK
S-3513B
Rev.1.2
_00
14
Seiko Instruments Inc.
4. Processing of none-existent data and end-of-month
When writing real-time data, validate it and treat any invalid data and end-of-month correction.
[None-existent data processing]
Table 11
Register
Normal data
Error data
Result
Year data
00 to 99
XA to XF, AX to FX
00
Month data
01 to 12
00, 13 to 19, XA to XF
01
Day data
01 to 31
00, 32 to 39, XA to XF
01
Day of week data
0 to 6
7
0
Hour data
*1
(24-hour)
(12-hour)
0 to 23
0 to 11
24 to 29, 3X, XA to XF
12 to 19, XA to XF
00
00
Minute data
00 to 59
60 to 79, XA to XF
00
Second data
*2
00 to 59
60 to 79, XA to XF
00
*1.
For 12-hour expression, write the AM/PM flag.
The AM/PM flag is ignored in 24-hour expression, but "0" for 0 to 11 o'clock and "1" for
12 to 23 o'clock are read in a read operation.
*2.
None-existent data processing for second data is performed by a carry pulse one second
after the end of writing. At this point, the carry pulse is sent to the minute counter.
[End-of-month correction]
Any none-existent day is corrected to the first day of the next month. For example, February 30 is
changed to March 1. Leap-year correction is also performed here.
REAL-TIME
CLOCK
Rev.1.2
_00
S-3513B
Seiko Instruments Inc.
15
5. Power voltage detecting circuit
S-3513B has an internal power voltage detecting circuit. This circuit gives sampling movement for
only 15.6 ms. once a second. If the power voltage decreases below the detection voltage (V
DET
), the BLD
latch circuit latches the "H" level, and sampling movement stops. Only when subsequent communication is
of the status read command, the output of the latch circuit is transferred to the sift register and the sampling
movement is resumed. Decrease in power voltage can be monitored by reading the POWER flag. That is
to say, once decrease in power voltage is detected, any detecting operation is not performed and "H" is held
unless you perform initialization or send the status read command.
Caution When power voltage is increased and the first read operation is performed after decrease
in power voltage occurs and the latch circuit latches "H", "1" can be read on the POWER
flag, however, if the next read operation is performed after the sampling of the detecting
circuit, the POWER flag is reset since sampling is subsequently allowed. See the timing
diagram below.
Latch circuit output
Sampling pulse
(0)
1 s
1 s
Stop
Stop
Stop
(1)
(1)
(1) (1)
(1) (1)
(0)
V
DD
POWER flag
V
DET
Communication
Latch circuit
output
Sampling pulse
Carry pulse
1 s
1 s
(1)
(0)
Communication
POWER flag
[Timing of sampling pulse]
0.5 s
0.5 s
7.8 ms
Carry-up timing
15.6 ms
Latch timing
1 Hz
Sampling pulse
(1)
(0)
V
DET
V
DD
Stop
Stop
Stop
Stop
Figure 12 Timing of the power voltage detecting circuit
REAL-TIME CLOCK
S-3513B
Rev.1.2
_00
16
Seiko Instruments Inc.
6. Example of software treatment
(1) Initialization flow at power-on
NO
YES
START
END
POWER
=1
*1.
If S-3513B is back-up and power is turned on
only on the CPU side, the reset command
does not need transferring.
*2.
If conditions are no good (e.g., noise) and
probable changes in commands occurs via
serial communications, it is recommended to
make sure the TEST flag.
*3.
The test ending command may be used
lternately.
Power on
Reset command
transfer
NO
YES
TEST
=1
Reset command
transfer
Status register setting
command transfer
Real-time data setting
command transfer
*1
*2
*3
Figure 13 Initialization flow
REAL-TIME
CLOCK
Rev.1.2
_00
S-3513B
Seiko Instruments Inc.
17
Samples of Application Circuits
V
CC
XOUT
XIN
S-3513BEFS
SIO
VSS
VDD
SCK
VSS
VCC
External CPU
F32K
CS
System
power
C
g
Due to the I/O pin with no protective diode on the VDD side, the relation of VCC
VDD has no
problem but give great care to the standard.
Make communications after the system power is turned on and a stable state is obtained.
Figure 14 Application circuit 1
VSS
VCC
External CPU
Power
switching
circuit
XOUT
XIN
S-3513BEFS
SIO
VSS
VDD
SCK
F32K
CS
System
power
C
g
Make communications after the system power is turned on and a stable state is obtained.
Figure 15 Application circuit 2
Caution The applied circuits above do not guarantee proper operation.
Evaluate in the actual application to determine the correct constants.
REAL-TIME CLOCK
S-3513B
Rev.1.2
_00
18
Seiko Instruments Inc.
Adjustment of Oscillating Frequency
1. Configuration of the oscillating circuit
Since crystal oscillation is sensitive to external noises (clock accuracy is affected), the following
measures are essential for optimizing your oscillating circuit configuration:
(1) Place S-3513B, crystal oscillator and external capacitor (C
g
) as close to each other as possible.
(2) Make high the insulation resistance between pins and the substrate wiring patterns of XIN and
XOUT.
(3) Do not place any signal or power lines close to the oscillating circuit.
XIN
XOUT
C
g
S-3513B
C
d
R
d
R
f
Crystal oscillator:32,768 Hz
C
L
=6 pF
C
g
=3 to 35 pF
Oscillating circuit internal constant standard
values:
R
f
=20 M
R
d
=220 K
C
d
=12 pF
Figure 16 Connection diagram
REAL-TIME
CLOCK
Rev.1.2
_00
S-3513B
Seiko Instruments Inc.
19
2. Measurement of oscillating frequencies
Referring to the circuit configuration in Figure 17, turn on the power and measure oscillating
frequencies with a frequency counter.
Remark If the error range is
5 ppm in relation to 32,768 Hz, time shifts by about 13 seconds a
month (as calculated using the following expression).
5
10
-6
(1 ppm)
60 seconds 60 minutes 24 hours 30 days = 13 seconds/month
Open
Frequency
counter
VDD
XIN
XOUT
SDA
F32K
VSS
CS
SCK
C
g
S-3513B
Figure 17 Connection diagram
Caution 1. Use a high-accuracy frequency counter (1 ppm order).
2. The 32,768 Hz signal is output uninterruptedly.
3. Determine C
g
with its frequency slow/fast range property referred.
REAL-TIME CLOCK
S-3513B
Rev.1.2
_00
20
Seiko Instruments Inc.
3. Adjustment of oscillating frequencies
Matching of a crystal oscillator with the nominal frequency must be performed with parasitic
capacitance on the board included. Select a crystal oscillator and optimize the C
g
value in accordance with
the flow chart below.
NO
YES
START
Variable
capacity
Select a crystal oscillator.
NO
Is C
g
in the
specification ?
*1
*2
Set C
g
NO
Is it an
optimal
value ?
YES
Change C
g
END
YES
Set to the center of
variable capacitor.
Does
the frequency
match ?
NO
YES
Make fine adjustment
of the frequency in
variable capacity.
*3
*3
<Trimer capacitor>
<Fixed capacitor>
Figure 18 Crystal oscillator setting flow
*1. For making matching adjustment of the IC with a crystal, contact an appropriate crystal maker to
determine the C
L
value (load capacity) and R
I
value (equivalent serial resistance). The C
L
value
= 6
pF and R
I
value
= 30 k Typ. are recommended values.
*2. C
g
value selection must be performed on the actual PCB since parasitic capacitance affects it. Select
the C
g
value in a range from 3 pF to 35 pF. If the frequency does not match, change the C
L
value of
the crystal.
*3. Adjust the rotation angle of the variable capacity so that the capacity value is somewhat smaller than
the center, and confirm the oscillating frequency and the center value of the variable capacity. This is
done in order to make the capacity of the center value smaller than one half of the actual capacity value
because a smaller capacity value makes a greater quantity of changes in a frequency. If the frequency
does not match, change the C
L
value of the crystal.
Caution 1. Oscillating frequencies are changed by ambient temperature and power voltage.
Refer to property samples.
2. The 32 kHz crystal oscillator operates slower at higher or lower ambient temperature
than 20 to 25
C. Therefore, it is recommended to adjust or set the oscillator to operate
somewhat faster at normal temperature.
REAL-TIME
CLOCK
Rev.1.2
_00
S-3513B
Seiko Instruments Inc.
21
Precautions
Do not apply an electrostatic discharge to this IC that exceeds the performance ratings ofthe built-in
electrostatic protection circuit.
SII claims no responsibility for any disputes arising out of or in connection with any infringement by
products including this IC of patents owned by a third party.
REAL-TIME CLOCK
S-3513B
Rev.1.2
_00
22
Seiko Instruments Inc.
Characteristics (Reference Data)
(1) Standby current vs. C
g
(2) Standby current vs. V
DD
(3) Operating drain current vs. Input clock
(4) Standby current vs. temperature
(5) Oscillating frequency vs. C
g
(6) Oscillating frequency vs. V
DD
SCK frequency
Ta
=25C
I
DD1
[
A]
0
1
2
3
4
5
6
0
0.5
1
1.5
2
2.5
3
V
DD
[V]
Ta [
C]
-30 -10
50
30
10
80
0
0.5
1
1.5
2
I
DD1
[
A]
Ta
=25C
0
400
1,000
0
50
100
150
I
DD2
[
A]
Ta
=25C
V
DD
[V]
0
2
4
6
-4
-2
0
2
4
f/f
[ppm]
Ta
=25C
C
g
[pF]
f/f
[ppm]
0
5
10
15
-20
0
20
40
60
80
V
DD
=5 V
V
DD
=3 V
0
5
10
15
0
0.5
1
1.5
2
Ta
=25C
C
g
[pF]
I
DD1
[
A]
V
DD
=5 V
V
DD
=3 V
V
DD
=3 V
V
DD
=5 V
V
DD
=3 V
V
DD
=5 V
REAL-TIME
CLOCK
Rev.1.2
_00
S-3513B
Seiko Instruments Inc.
23
f/f
[ppm]
(8) Oscillation start time vs. C
g
Ta
=25C
(9) Output current 1 (V
OUT
vs. I
OL1
)
(7) Oscillating frequency vs. temperature
(10) Output current 2 (V
OUT
vs. I
OL2
)
C
g
[pF]
T
STA
[mS]
0
5
10
15
0
200
400
600
800
-50
0
50
100
-160
-120
-80
-40
20
Ta
=25C
,
V
DD
=3 V
Ta [
C]
V
DD
=5 V
V
DD
=3 V
F32K pins, Ta
=25C
SIO pin, Ta
=25C
V
OUT
[V]
0
1
2
3
4
5
0
5
10
15
0
1
2
3
4
5
0
10
20
30
40
50
I
OL1
[mA]
V
DD
=5 V
V
DD
=3 V
V
DD
=5 V
V
DD
=3 V
V
OUT
[V]
I
OL2
[mA]
No.
TITLE
SCALE
UNIT
mm
Seiko Instruments Inc.
0.220.1
0.65
3.10.3
1
8
5
4
0.15
+0.1
-0.05
SSOP8-A-PKG Dimensions
No. FS008-A-P-SD-1.1
FS008-A-P-SD-1.1
No.
TITLE
SCALE
UNIT
mm
Seiko Instruments Inc.
6.90.1
(4.0)
1.40.1
0.30.05
8.00.1
1.550.05
1.550.05
4.00.1
2.00.05
Feed direction
SSOP8-A-Carrier Tape
No. FS008-A-C-SD-1.1
FS008-A-C-SD-1.1
No.
TITLE
SCALE
UNIT
mm
Seiko Instruments Inc.
20.5
130.2
210.8
20.5
13.50.5
QTY.
2,000
Enlarged drawing in the central part
SSOP8-A-Reel
No. FS008-A-R-SD-1.1
FS008-A-R-SD-1.1
The information described herein is subject to change without notice.
Seiko Instruments Inc. is not responsible for any problems caused by circuits or diagrams described herein
whose related industrial properties, patents, or other rights belong to third parties. The application circuit
examples explain typical applications of the products, and do not guarantee the success of any specific
mass-production design.
When the products described herein are regulated products subject to the Wassenaar Arrangement or other
agreements, they may not be exported without authorization from the appropriate governmental authority.
Use of the information described herein for other purposes and/or reproduction or copying without the
express permission of Seiko Instruments Inc. is strictly prohibited.
The products described herein cannot be used as part of any device or equipment affecting the human
body, such as exercise equipment, medical equipment, security systems, gas equipment, or any apparatus
installed in airplanes and other vehicles, without prior written permission of Seiko Instruments Inc.
Although Seiko Instruments Inc. exerts the greatest possible effort to ensure high quality and reliability, the
failure or malfunction of semiconductor products may occur. The user of these products should therefore
give thorough consideration to safety design, including redundancy, fire-prevention measures, and
malfunction prevention, to prevent any accidents, fires, or community damage that may ensue.
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