S-35391A
www.ablic.com
© ABLIC Inc., 2014-2018
2-WIRE REAL-TIME CLOCK
Rev.2.1
_04
The S-35391A is a CMOS 2-wire real-time clock IC which operates with the very low current consumption in the wide range of
operation voltage. The operation voltage is 1.3 V to 5.5 V so that the S-35391A can be used for various power supplies from
main supply to backup battery. Due to the 0.25
A
current consumption and wide range of power supply voltage at time
keeping, the S-35391A makes the battery life longer. In the system which operates with a backup battery, the included free
registers can be used as the function for user's backup memory. Users always can take back the information in the registers
which is stored before power-off the main power supply, after the voltage is restored.
The S-35391A has the function to correct advance / delay of the clock data speed, in the wide range, which is caused by the
crystal oscillation circuit's frequency deviation. Correcting according to the temperature change by combining this function
and a temperature sensor, it is possible to make a high precise clock function which is not affected by the ambient
temperature.
Features
Low current consumption:
0.25
A
typ. (V
DD
= 3.0 V, Ta =
25C)
Wide range of operating voltage:
1.3 V to 5.5 V
Built-in clock correction function
Built-in free user register
2-wire (I
2
C-bus) CPU interface
Built-in alarm interrupter
Built-in flag generator during detection of low power voltage or at power-on
Auto calendar up to the year 2099, automatic leap year calculation function
Built-in constant voltage circuit
Built-in 32.768 kHz crystal oscillation circuit (built-in C
d
, external C
g
)
*1
Lead-free, Sn 100%, halogen-free
*1.
Refer to "
Product Name Structure"
for details.
Applications
Mobile game device
Mobile AV device
Digital still camera
Digital video camera
Electronic power meter
DVD recorder
TV, VCR
Mobile phone, PHS
Packages
8-Pin SOP (JEDEC)
SNT-8A
1
2-WIRE REAL-TIME CLOCK
S-35391A
Block Diagram
Rev.2.1
_04
XIN
XOUT
Oscillation
circuit
Divider,
timing generator
INT1 register
INT1
controller
INT1
Clock correction register
Status register 1
Status register 2
Comparator 1
Real-time data register
Second Minute Hour
Day of
Day Month Year
the week
Comparator 2
Free register
Low power supply
voltage detector
Power-on
detection circuit
Constant-voltage
circuit
VSS
INT2 register
INT2
controller
Serial
interface
SDA
SCL
INT2
VDD
Shift register
Figure 1
2
Rev.2.1
_04
Product Name Structure
1. Product name
1. 1
8-Pin SOP (JEDEC)
2-WIRE REAL-TIME CLOCK
S-35391A
S-35391A -
J8T1
x
Environmental code
U:
Lead-free (Sn 100%), halogen-free
G:
Lead-free (for details, please contact our sales office)
Package name (abbreviation) and IC packing specification
*1
J8T1: 8-Pin SOP (JEDEC), Tape
Product name
*1.
Refer to the tape drawing.
1. 2
SNT-8A
S-35391A -
I8T1
U
Environmental code
U:
Lead-free (Sn 100%), halogen-free
Package name (abbreviation) and IC packing specification
*1
I8T1: SNT-8A, Tape
Product name
*1.
Refer to the tape drawing.
2. Packages
Table 1 Package Drawing Codes
Package Name
8-Pin SOP (JEDEC)
SNT-8A
Environmental code = G
Environmental code = U
Dimension
FJ008-A-P-SD
FJ008-A-P-SD
PH008-A-P-SD
Tape
FJ008-D-C-SD
FJ008-D-C-SD
PH008-A-C-SD
Reel
FJ008-D-R-SD
FJ008-D-R-S1
PH008-A-R-SD
Land
PH008-A-L-SD
3
2-WIRE REAL-TIME CLOCK
S-35391A
Pin Configuration
1. 8-Pin SOP (JEDEC)
Top view
1
2
3
4
8
7
6
5
Rev.2.1
_04
Table 2 List of Pins
Pin No
1
2
Symbol
Description
Output pin for
interrupt signal 1
Connection pins
for quartz crystal
I/O
Output
Configuration
Nch open-drain output
(no protective diode at VDD)
INT 1
XOUT
3
4
5
6
7
XIN
VSS
INT2
Figure 2 S-35391A-J8T1x
SCL
SDA
VDD
GND pin
Output pin for
interrupt signal 2
Input pin for
serial clock
I/O pin for serial
data
Pin for positive
power supply
2. SNT-8A
Top view
1
2
3
4
8
7
6
5
Nch open-drain output
(no protective diode at VDD)
CMOS input
Input
(no protective diode at VDD)
Nch open-drain output
Bi-directional (no protective diode at VDD)
CMOS input
Output
8
Figure 3 S-35391A-I8T1U
Remark 1.
x: G or U
2.
Please select products of environmental code = U for Sn 100%, halogen-free products.
4
Rev.2.1
_04
Pin Functions
1. SDA (I/O for serial data) pin
2-WIRE REAL-TIME CLOCK
S-35391A
This is a data input / output pin of I
2
C-bus interface. This pin inputs / outputs data by synchronizing with a clock pulse
from the SCL pin. This pin has CMOS input and Nch open drain output. Generally in use, pull up this pin to the VDD
potential via a resistor, and connect it to any other device having open drain or open collector output with wired-OR
connection.
2. SCL (input for serial clock) pin
This pin is to input a clock pulse for I
2
C-bus interface. The SDA pin inputs / outputs data by synchronizing with the
clock pulse.
3. XIN, XOUT (quartz crystal connect) pins
Connect a quartz crystal between XIN and XOUT.
4.
INT1
(output for interrupt signal 1) pin
This pin outputs a signal of interrupt, or a clock pulse. By using the status register 2, users can select either of; alarm 1
interrupt, output of user-set frequency, minute-periodical interrupt 1, minute-periodical interrupt 2, or 32.768 kHz output.
This pin has Nch open drain output.
5.
INT2
(output for interrupt signal 2) pin
This pin outputs a signal of interrupt, or a clock pulse. By using the status register 2, users can select either of; alarm 2
interrupt, output of user-set frequency, or minute-periodical interrupt 1. This pin has Nch open drain output.
6. VDD (positive power supply) pin
Connect this VDD pin with a positive power supply. Regarding the values of voltage to be applied, refer to
"
Recommended Operation Conditions
".
7. VSS pin
Connect this VSS pin to GND.
Equivalent Circuits of Pins
SDA
SCL
Figure 4 SDA Pin
INT1, INT2
Figure 5 SCL Pin
Figure 6
INT1
Pin,
INT2
Pin
5
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