S-35390A-I8T1G

Manufacturer Part NumberS-35390A-I8T1G
DescriptionIC REAL TIME CLOCK 2WIRE SNT-8A
ManufacturerSeiko Instruments
TypeClock/Calendar
S-35390A-I8T1G datasheet
 


Specifications of S-35390A-I8T1G

Time FormatHH:MM:SS (12/24 hr)Date FormatYY-MM-DD-dd
InterfaceI²C, 2-Wire SerialVoltage - Supply1.3 V ~ 5.5 V
Operating Temperature-40°C ~ 85°CMounting TypeSurface Mount
Package / CaseSNT-8ALead Free Status / RoHS StatusLead free / RoHS Compliant
Memory Size-Other names728-1059-2
S-35390A-I8T1G
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© Seiko Instruments Inc., 2004-2010
The S-35390A is a CMOS 2-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 0.25 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 :
• Wide range of operating voltage :
• 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 oscillator (C
• Lead-free, Sn 100%, halogen-free
*1. Refer to “ Product Name Structure” for details.
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
Packages
• 8-Pin SOP (JEDEC)
• 8-Pin TSSOP
• SNT-8A
0.25 μA typ. (V
= 3.0 V, Ta = 25°C)
DD
1.3 to 5.5 V
built in, C
external)
d
g
*1
Seiko Instruments Inc.
S-35390A
2-WIRE REAL-TIME CLOCK
Rev.3.0
_00
1

S-35390A-I8T1G Summary of contents

  • Page 1

    ... The S-35390A is a CMOS 2-wire real-time clock IC which operates with the very low current consumption and in the wide range of operation voltage. The operation voltage that this IC can be used for various power supplies from main supply to backup battery. Due to the 0.25 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’ ...

  • Page 2

    ... REAL-TIME CLOCK S-35390A Pin Configuration Remark Please select products of environmental code = U for Sn 100%, halogen-free products. List of Pin Pin No. Symbol Description Output pin for 1 INT 1 interrupt signal 1 2 XOUT Connection pin for crystal oscillator 3 XIN 4 VSS GND pin Output pin for ...

  • Page 3

    ... This pin outputs a signal of interrupt clock pulse. By using the status register 2, users can select either of; alarm 1 interrupt, output of user-set frequency, per-minute edge interrupt, minute-periodical interrupt 1, minute-periodical interrupt 2, or 32.768 kHz output. This pin has Nch open drain output. ...

  • Page 4

    ... Power-on detection circuit Constant-voltage circuit VSS 4 Diviver, INT1 register Comparator 1 Second Minute Hour Comparator 2 INT2 register Shift register Figure 7 Seiko Instruments Inc. Rev.3.0 INT1 controller Real-time data register Day of Day Month Year the week INT2 controller Serial interface _00 INT1 INT2 ...

  • Page 5

    ... Crystal oscillator C value *1. The power supply voltage that allows communication under the conditions shown in Table 8 of “ Characteristics” . *2. The power supply voltage that allows time keeping. For the relationship with V detection voltage), refer to “ Characteristics (Typical Data)” . Oscillation Characteristics (Ta = 25° ...

  • Page 6

    ... SCL, SDA − SCL, SDA INT , 1 INT 0.4 V OUT SDA V = 0.4 V OUT − − Seiko Instruments Inc 9.1 pF) manufactured by Seiko Instruments Inc.) g Min. Typ. − 0.25 − 6 −0.5 − −0.5 − −0.5 − − 0.5 − 0.8 × V − − 0.3 − ...

  • Page 7

    ... SCL, SDA rise time SCL, SDA fall time Bus release time Noise suppression time *1. Since the output format of the SDA pin is Nch open-drain output, SDA output delay time is determined by the values of the load resistance (R ) and load capacity (C L *2. Regarding the power supply voltage, refer to “ Recommended Operation Conditions”. ...

  • Page 8

    ... Read/Write command to the SDA bus. After that, output or input is performed from B7 of data. If data I/O has been completed, finish communication by inputting a stop condition to the S-35390A. The master device generates an acknowledgment signal for every 1-byte. Regarding details, refer to “ ...

  • Page 9

    ... Read-only flag. Valid only when using the alarm function. When the alarm time matches, this flag is set to “1”, and it is cleared to “0” when Read. *4. Read-only flag. “POC” is set to “1” when power is applied cleared to “0” when Read. Regarding “BLD”, refer to “ Low Power Supply Voltage Detection Circuit”. ...

  • Page 10

    ... BCD code. To Write/Read real-time data 1 access, transmit/receive the data of year in B7, month, day, day of the week, hour, minute, second in B0, in 7-byte. When you skip the procedure to access the data of year, month, day, day of the week, Read/Write real-time data 2 access. In this case, transmit/receive the data of hour in B7, minute, second in B0, in 3-byte ...

  • Page 11

    ... Feb. (leap year 28: Feb. (non-leap year) Example: 29 (D1, D2, D4, D8, D10, D20 ( Day of the week data (00 to 06): W1, W2 septenary up counter. Day of the week is counted in the order of 00, 01, 02, …, 06, and 00. Set up day of the week and the count value. Hour data ( 11): H1, H2, H4, H8, H10, H20 12-hour expression, write 0 ...

  • Page 12

    ... The INT1 flag in “1” at alarm 1 interrupt mode, the INT2 flag in “1” at alarm 2 interrupt mode. Set “0” in INT1AE (B5 in the status register INT2AE (B1 in the status register 2) after reading “1” in the INT1 flag or in the INT2 flag. This flag is Read-only. This flag is read once, is set to “0” automatically. ...

  • Page 13

    ... R/W R TEST This is a test flag for SII. Be sure to set this flag to “0” in use. If this flag is set to “1”, be sure to initialize to set “0” INT2AE INT2ME INT2FE These bits are used to select the output mode for the alarm 2 interrupt, set alarm interrupt mode, then access the INT2 register. ...

  • Page 14

    ... S-35390A 4. INT1 register and INT2 register The INT1 and INT2 registers are to set up the output of user-set frequency set up alarm interrupt. Users are able to switch the output mode by using the status register 2. If selecting to use the output mode for alarm interrupt by status register 2 ...

  • Page 15

    ... Output of user-set frequency The INT1 and INT2 registers are 1-byte data registers to set up the output frequency. Setting each bit the register to “1”, the frequency which corresponds to the bit is output in the AND-form. SC2 to SC4 in the INT1 register, and SC5 to SC7 in the INT2 register are 3-bit SRAM type registers that can be freely set by users. ...

  • Page 16

    ... REAL-TIME CLOCK S-35390A 5. Clock-correction register The clock-correction register is a 1-byte register that is used to correct advance/delay of the clock. When not using this function, set this register to “00h”. Regarding the register values, refer to “ Function to Clock-Correction” R/W R/W 6. Free register This free register is a 1-byte SRAM type register that can be set freely by users ...

  • Page 17

    ... V within 10 ms after setting the IC’s power supply voltage When the power-on detection circuit is not working normally is; the POC flag (B0 in the status register) is not in “1” not output from the pin. In this case, power-on the S-35390A once again because the internal data may be in the indefinite status. ...

  • Page 18

    ... Input from master device Figure 21 Data of Status Register 1 at Initialization 18 00 (Y), 01 (M), 01 (D), 0 (day of the week), 00 (H), 00 (M), 00 (S) “ b” (In B6, B5, B4, the data of B6, B5 the status register 1 at initialization is set. Refer to Figure 21.) “00h” “00h” “00h” ...

  • Page 19

    ... Without initializing, Read in the next BLD flag is done after sampling, the BLD flag gets reset to “0”. In this case, be sure to initialize although the BLD flag is in “0” because the internal circuit may be in the indefinite status ...

  • Page 20

    ... AM In 24-hour expression, the are able to read 11 23. *2. Processing of nonexistent data, regarding second data, is done by a carry pulse which is generated one sec after, after Write. At this point the carry pulse is sent to the minute-counter. 2. Correction of end-of-month A nonexistent day, such as February 30 and April 31, is set to the first day of the next month. ...

  • Page 21

    ... If setting the pin output to “H”, turn off the alarm function by setting “0” in INT1AE/INT2AE in the status register 2. To set the alarm time, set the data of day of the week, hour and minute in the INT1/INT2 register. Refer to “4. INT1 register and INT2 register” in “ Configuration of Register”. ...

  • Page 22

    ... If users clear INT1AE/INT2AE once; “L” is not output from the again, within a period when the alarm time matches real-time data. *2. If turning the alarm output on by changing the program, within the period when the alarm time matches real-time data, “L” is output again from the 2 ...

  • Page 23

    ... INT1 pin/INT2 pin "L" is output again if this period is within 7.9 ms *1. Pin output is set to “H” by disabling the output mode within 7.9 ms, because the signal of this procedure is maintained for 7.9 ms. Note that pin output is set to “L” by setting enable the output mode again. ...

  • Page 24

    ... However, in Read in the real-time data register, the procedure delays at max. 0.5 sec thus output “L” from the real-time data register, some delay is made in the output period due to Write timing and the second-data during Write. (a) During normal operation ...

  • Page 25

    ... The function to clock-correction is to correct advance/delay of the clock due to the deviation of oscillation frequency, in order to make a high precise clock. For correction, the S-35390A adjusts the clock pulse by using a certain part of the dividing circuit, not adjusting the frequency of the crystal oscillator. Correction is performed once every 20 seconds (or 60 seconds). The minimum resolution is approx. 3 ppm (or approx. 1 ppm) and the S-35390A corrects in the range of − ...

  • Page 26

    ... Correction value Caution The figure range which can be corrected is that the calculated value is from 0 to 64. *1. Convert this value to be set in the clock correction register. For how to convert, refer to “(a) Calculation example 1”. *2. Measurement value when 1 Hz clock pulse is output from the *3 ...

  • Page 27

    ... Rev.3.0 _00 2. Setting value for register and correction value Table 14 Setting Value for Register and Correction Value (Minimum Resolution: 3.052 ppm ( Table 15 Setting Value for Register and Correction Value (Minimum Resolution: 1.017 ppm ( Correction Value • • • • ...

  • Page 28

    ... How to confirm setting value for register and result of correction The S-35390A does not adjust the frequency of the crystal oscillation by using the clock-correction function. Therefore users cannot confirm corrected or not by measuring output 32.768 kHz. When the function to clock-correction is being used, the cycle clock pulse output from the Figure 31 ...

  • Page 29

    ... A start condition is when the SDA line changes “H” to “L” when the SCL line is in “H”, so that the access starts. 2. Stop condition A stop condition is when the SDA line changes “L” to “H” when the SCL line is in “H”, and the access stops, so that the S-35390A gets standby. ...

  • Page 30

    ... After detecting a start condition, the S-35390A receives device code and command. The S-35390A enters the Read-data mode by the Read/Write bit “1”. The data is output from B7 in 1-byte. Input an acknowledgment signal from the master device every moment that the S-35390A outputs 1-byte data. However, do not input an acknowledgment signal (input NO_ACK) for the last data-byte output from the master device ...

  • Page 31

    ... After detecting a start condition, S-35390A receives device code and command. The S-35390A enters the Write-data mode by the Read/Write bit “0”. Input data from 1-byte. The S-35390A outputs an acknowledgment signal (“L”) every moment that 1-byte data is input. After receiving the acknowledgment signal which is for the last byte-data, input a stop condition to the S-35390A to finish access ...

  • Page 32

    ... SDA Device code + command I/O mode switching *1. Set NO_ACK = 1 in Read. *2. Transmit ACK = 0 from the master device to the S-35390A in Read. (3) Status register 1 access and status register 2 access SCL SDA * Status register 1 selected Status register 2 selected *2. Set NO_ACK = 1 for reading. Figure 40 Status Register 1 Access and Status Register 2 Access ...

  • Page 33

    ... INT1 register access and INT2 register access In Read/Write the INT1 and INT2 registers, data varies depending on the setting of the status register 2. Be sure to Read/Write after setting the status register 2. When setting the alarm by using the status register 2, these registers work as 3-byte alarm time data registers, in other statuses, they work as 1-byte registers. When outputting the user-set frequency, they are the data registers to set up the frequency. Regarding details of each data, refer to “ ...

  • Page 34

    ... REAL-TIME CLOCK S-35390A (5) Clock correction register access SCL SDA I/O mode switching *1. Set NO_ACK = 1 in Read. (6) Free register access SCL SDA I/O mode switching *1. Set NO_ACK = 1 in Read R Device code + command Clock correction data I/O mode switching Figure 43 Clock Correction Register Access ...

  • Page 35

    ... S-35390A does not operate the next procedure because the internal circuit keeps the state prior to interruption. The S-35390A does not have a reset pin so that users usually reset its internal circuit by inputting a stop condition. However, if the SDA line is outputting “L” (during output of acknowledgment signal or Read), the S-35390A does not accept a stop condition from the master device ...

  • Page 36

    ... Figure 46 shows the flowchart of initialization at power-on and an example of real-time data set-up. Regarding how to apply power, refer to “ Power-on Detection Circuit and Register Status” unnecessary for users to comply with this flowchart of real-time data strictly. And if using the default data at initializing also unnecessary to set up again. Wait for 0.5 s Read status register 1 ...

  • Page 37

    ... S-35390A VSS XIN XOUT C g Caution 1. Because the I/O pin has no protective diode on the VDD side, the relation of V but pay careful attention to the specifications. 2. Start communication under stable condition after power-on the power supply in the system. VDD S-35390A VSS XOUT ...

  • Page 38

    ... REAL-TIME CLOCK S-35390A Adjustment of Oscillation Frequency 1. Configuration of oscillator Since crystal oscillation is sensitive to external noise (the clock accuracy is affected), the following measures are essential for optimizing the oscillation configuration. (1) Place the S-35390A, crystal oscillator, and external capacitor (C (2) Increase the insulation resistance between pins and the substrate wiring patterns of XIN and XOUT. ...

  • Page 39

    ... signal is not output, the power-on detector does not operate normally. Turn off the power and then turn it on again. For how to apply power, refer to “ Power-on Detection Circuit and Register Status” . Remark If the error range is ± 1 ppm in relation to 1 Hz, the time is shifted by approximately 2.6 seconds per month (calculated using the following expression). ...

  • Page 40

    ... Adjust the rotation angle of the variable capacitance so that the capacitance value is slightly smaller than the center, and confirm the oscillation frequency and the center value of the variable capacitance. This is done in order to make the capacitance of the center value smaller than one half of the actual capacitance value because a smaller capacitance value increases the frequency variation ...

  • Page 41

    ... Although the IC contains a static electricity protection circuit, static electricity or voltage that exceeds the limit of the protection circuit should not be applied. • Seiko Instruments Inc. assumes no responsibility for the way in which this IC is used in products created using this IC or for the specifications of that product, nor does Seiko Instruments Inc. assume any responsibility for any infringement of patents or copyrights by products that include this IC either in Japan or in other countries ...

  • Page 42

    ... SCLfrequency [kHz] (5) Standby current vs. C characteristics 25°C, C 1.0 0.9 0.8 0.7 0.6 I DD1 0.5 [μA] 0.4 0 (2) Current consumption when 32 kHz is output vs DD3 [μ [V] (4) Standby current vs. Temperature characteristics = DD1 [μA] 300 400 500 (6) Oscillation frequency vs Δf/f [ppm 5.0 V ...

  • Page 43

    ... V DD (9) Oscillation start time vs 500 450 400 350 300 t STA 250 V [ms] DD 200 150 100 (11) Output current characteristics 2 (V SDA pin ° 5 OL2 [mA 0 OUT characteristics (8) Oscillation frequency vs. Temperature DD characteristics = 7 Δf/f [ppm [V] characteristics (10) Output current characteristics 25°C ...

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    ... 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. ...