Rev.1.2
_00
3-WIRE REAL-TIME CLOCK
S-35192A
The S-35192A is a CMOS 3-wire real-time clock IC which operates with the very low current
consumption and in the wide range of operation voltage. The operation voltage is 1.3 V to 5.5
V so that this IC can be used for various power supplies from main supply to backup battery.
Due to the 0.45
µA
current consumption and wide range of power supply voltage at time
keeping, this IC 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.
This IC has the function to correct advance/delay of the clock data speed, in the wide range,
which is caused by the 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 :
0.45
µA
typ. (V
DD
=
3.0 V, Ta
=
25°C)
Constant output of 32.768 kHz clock pulse (Nch open-drain output)
Wide range of operating voltage :
1.3 to 5.5 V
Built-in clock-correction function
Built-in free user register
3-wire (MICROWIRE) CPU interface
Built-in alarm function
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 oscillator (C
d
built in, C
g
external)
Package : SNT-8A
Lead-free product
Applications
•
•
•
•
•
•
•
•
•
Mobile game devices
Mobile AV devices
Digital still cameras
Digital video cameras
Electronic power meters
DVD recorders
TVs, VCRs
Mobile phones, PHS
Car navigation
Package
Package Name
SNT-8A
Drawing Code
Package
PH008-A
Tape
PH008-A
Reel
PH008-A
Land
PH008-A
Seiko Instruments Inc.
1
3-WIRE REAL-TIME CLOCK
S-35192A
Pin Configuration
SNT-8A
Top view
32KO
XOUT
XIN
VSS
Figure 1
Rev.1.2
_00
1
2
3
4
8
7
6
5
VDD
SIO
SCK
CS
Pin Configuration (S-35192A-I8T1G)
List of Pin
Table 1
Pin No.
1
2
3
4
5
6
7
8
Symbol
32KO
XOUT
XIN
VSS
CS
Description
Pin for constant output of
32.768 kHz
Connection pin for crystal
oscillator
GND pin
Input pin for chip select
Input pin for serial clock
I/O pin for serial data
Pin for positive power supply
I/O
Output
−
−
Configuration
Nch open-drain output
(no protective diode at VDD)
−
−
SCK
SIO
VDD
CMOS input
Input
(built-in pull-down resistor. 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
−
−
2
Seiko Instruments Inc.
Rev.1.2
_00
Pin Function
•
CS (input for chip select) pin
3-WIRE REAL-TIME CLOCK
S-35192A
This pin is to input chip select, has a pull-down resistor. Communication is available when this pin is in “H” level. If not
using communication, set this pin “L” or open.
•
SCK
(input for serial clock) pin
This pin is to input a clock pulse for serial interface. When the CS pin is in “H”, the SIO pin inputs/outputs data by
synchronizing with the clock pulse. When the CS pin is in “L” or open, the
SCK
pin does not accept inputting a clock
pulse.
•
SIO (I/O for serial data) pin
This pin is to data input/output for serial interface. When the CS pin is in “H”, the SIO pin inputs/outputs data by
synchronizing with a clock pulse from the
SCK
pin. The status is in high impedance when the CS pin is in “L” or open,
so that the S-35192A does not transmit data. Setting the CS pin to “H” level from “L” or open, this SIO pin goes in the
input status so that it receives the command data. This pin has CMOS input and Nch open drain output.
•
XIN, XOUT (crystal oscillator connect) pin
Connect a crystal oscillator between XIN and XOUT.
•
32KO (constant output of 32.768 kHz) pin
This is an output pin for 32.768 kHz. This pin constantly outputs a clock pulse after power-on.
•
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”.
•
VSS pin
Connect this VSS pin to GND.
Equivalent Circuits of I/O Pin
SCK
SIO
Figure 2
SCK
pin
Figure 3
SIO pin
CS
32KO
Figure 4
CS pin
Figure 5 32KO pin
Seiko Instruments Inc.
3
3-WIRE REAL-TIME CLOCK
S-35192A
Block Diagram
Rev.1.2
_00
XIN
XOUT
Divider,
Oscillator
timing generator
INT register 1
INT
controller 1
Clock correction register
Status register 1
Status register 2
Comparator 1
Real-time data register
Day of
Second Minute Hour
Day Month Year
the week
Comparator 2
32KO
Free register
Low power supply
voltage detector
Power-on
detector
Constant-voltage
circuit
VSS
INT register 2
INT
controller 2
Serial
interface
SIO
SCK
CS
VDD
Shift register
Figure 6
4
Seiko Instruments Inc.
Rev.1.2
_00
Absolute Maximum Ratings
Table 2
Parameter
Power supply voltage
Input voltage
Symbol
V
DD
V
IN
Applicable Pin
−
CS,
SCK
, SIO
3-WIRE REAL-TIME CLOCK
S-35192A
Rating
V
SS
−
0.3 to V
SS
+ 6.5
V
SS
−
0.3 to V
SS
+ 6.5
Unit
V
V
Output voltage
V
OUT
SIO, 32KO
V
SS
−
0.3 to V
SS
+ 6.5
V
Operating ambient
T
opr
−
−40
to +85
°C
*1
temperature
Storage temperature
T
stg
−
−55
to +125
°C
*1.
Conditions with no condensation or frost. Condensation and frost cause short circuiting between pins, resulting in a
malfunction.
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 Operation Conditions
Table 3
(V
SS
= 0 V)
Parameter
Symbol
Conditions
Min.
Typ.
Max.
Unit
*1
Power supply voltage
Ta =
−40
to +85°C
1.3
3.0
5.5
V
V
DD
V
DDT
Time keeping power
−
5.5
V
Ta =
−40
to +85°C
V
DET
−
0.15
*2
supply voltage
Crystal oscillator C
L
value C
L
−
−
6
7
pF
*1.
The power supply voltage that allows communication under the conditions shown in
Table 8
of
“ AC Electrical
Characteristics”.
*2.
The power supply voltage that allows time keeping. For the relationship with V
DET
(low power supply voltage detection
voltage), refer to
“ Characteristics (Typical Data)”.
Oscillation Characteristics
Table 4
(Ta = 25°C, V
DD
= 3.0 V, V
SS
= 0 V, VT-200 crystal oscillator (C
L
= 6 pF, 32.768 kHz) 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
External capacitance
Internal oscillation capacitance
*1.
Reference value
V
STA
t
STA
δIC
δV
C
g
C
d
Within 10 seconds
−
−
V
DD
= 1.3 to 5.5 V
Applied to XIN pin
Applied to XOUT pin
1.1
−
−10
−3
−
−
−
−
−
−
−
8
5.5
1
+10
+3
9.1
−
V
s
ppm
ppm/V
pF
pF
Seiko Instruments Inc.
5
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