Contents

Features .............................................................. 1
Applications ......................................................... 1
Block Diagram ..................................................... 1
Pin Assignment ................................................... 2
Description of Terminals ...................................... 2
Description of Operation ...................................... 3
Samples of Applied Circuits................................. 15
Dimensional Outline Diagram (Unit:mm).............. 16
Order Specification .............................................. 16
Adjastment of Oscillating Frequency ................... 17
Absolute Maximum Ratings ................................. 19
Recommended Operating Conditions .................. 19
Oscillation Characteristics ................................... 19
DC Electrical Characteristics ............................... 20
AC Electrical Characteristics ............................... 22
Sample of Properties (Reference values) ............ 25

Frequently Asked Questions.................................27

Seiko Instruments Inc.

S-3511A 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. It

provides connection with a CPU via three wires and has an

interrupt/alarm feature, allowing the alleviation of software treatment on

the side of a host.

It also works on lower power with the oscillating circuit operated at a

constant voltage. Its package uses an extremely small and thin type of

eight-pin SSOP.

Block Diagram

Figure 1 Block diagram

Real-Time Clock

S-3511A

Features

Low power consumption

: 0.7

A typ. (V

=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

Built-in alarm interrupter

Steady-state interrupt frequency/duty setting feature

Built-in 32 KHZ crystal oscillating circuit (Internal Cd, External Cg)

8-pin SSOP package (terminal pitch: 0.65 mm)

Block Diagram

Applications

Cellular phone

PHS

A variety of pagers

TV set and VCR

Camera

INT Register

Status register

Oscillating

circuit

SCK

Timing

generation

Power voltage

detecting

circuit

Constant

voltage

circuit

Comparator

Second

Minute

Hour

Day of

week

Day

Month

Year

Shift register

Serial

Interface

INT

XIN

XOUT

Clock

generating

circuit

SIO

Real-Time Clock
S-3511A

Seiko Instruments Inc.

Pin Assignment

Description of Terminals

Terminal
Num.

Abbreviation

Description

Configuration

INT

Alarm interrupt output terminal.

Depending on the mode set by the INT
register and status register, it outputs low
or Clock when time is reached. It is
disabled by rewriting the status register.

N-channel open drain output
(No protective diode on the
side of VDD)

XIN

XOUT

Crystal oscillator connect terminal (32,768 HZ)

(Internal Cd, External Cg)

�

VSS

Negative power supply terminal (GND)

�

Chip select input terminal.

During "H": The SIO terminal allows data

input/output.
The SCK terminal allows data
input.

During "L": The SIO terminal is in the High-Z

state.

The SCK terminal is in the input-disabled state.

CMOS input (Included pull-
down resistance. No
protective diode on the side
of VDD)

SCK

Serial clock input terminal.

The input/output of data from the SIO
terminal is performed in synchronization with
this clock. However, the clock is not accepted
while the CD terminal is "L."

CMOS input (No protective
diode on the side of VDD)

SIO

Serial data input/output terminal.

It is normally in the High-Z state while the
CS terminal is "L." When the CS terminal
changes from "L" to "H", the SIO terminal
is set to an input terminal. It will be set to
an input or output terminal, depending on
an subsequently input command.

N channel open drain output
(No protective diode aon the
side of VDD)
CMOS input

VDD

Positive power supply terminal.

�

Table 1 Description of terminals

Figure 2

Pin assignment

8-Pin SSOP

Top view

XOUT

VSS

SIO

VDD

SCK

XIN

INT

Real-Time Clock

S-3511A

Seiko Instruments Inc.

Description of Operation

Serial interface

S-3511A receives various commands via a three-wire serial interface to read/write data. This section covers the transfer methods of

this product.

1-1. Data reading

When you input data from the SIO terminal in synchronization with the falling of the SCK terminal after turning the CS

terminal to "H", the data is included into the inside of S-3511A 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.

[Note] 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.

TEST

Output mode switching

(1) Real-time data reading 1

SCK

SIO

SCK

(3) Status register reading

Year data

Second data

Output mode switching

SIO

Status data

Input mode switching

LSB

MSB

Figure 3 Read communication

TEST

Output mode switching

(2) Real-time data reading 2

SCK

SIO

Hour data

Second data

LSB

MSB

LSB

MSB

LSB

MSB

LSB

MSB

Input mode switching

Command

LSB

MSB

LSB

MSB

LSB

MSB

POWER

Real-Time Clock
S-3511A

Seiko Instruments Inc.

1-2. Data writing

When you input data from the SIO terminal in synchronization with the falling of the SCK terminal after turning the CS
terminal to "H", the data is included into the inside of S-3511A at the eighth rising of the SCK clock and the state of data
reading 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.

TEST

(1) Real-time data writing 1

SCK

SIO

SCK

(3) Status register writing

Year data

Second data

SIO

Status data

LSB

MSB

Figure 4 Write communication

TEST

(2) Real-time data writing 2

SCK

SIO

Hour data

Second data

LSB

MSB

LSB

MSB

LSB

MSB

LSB

MSB

Command

MSB

LSB

MSB

LSB

MSB

LSB

POWER

Real-Time Clock

S-3511A

Seiko Instruments Inc.

1-3.Communication data configuration

After turning the CS terminal to "H", send four-bit fixed code "0110" and succeedingly transfer the command of a 3-bit

length and read/write command of a one-bit length.

Command configuration

There are seven 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.

Description

Reset (00 (year), 01 (month), 01 (day), 0 (day of week),

00 (minute), 00 (second)) (*1)

Status register access

Real-time data access 1 (year data to)

Real-time data access 2 (hour data to)

Alarm time/frequency duty setting 1

Alarm time/frequency duty setting 2

Test mode start (*2)

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.

Table 2 Command list

Figure 5 Communication data

Command

R/W

Fixed code

MSB

LSB

Read/Write bit

Real-Time Clock
S-3511A

Seiko Instruments Inc.

2-1. Real-time data register

The real-time data register is a fifty-six-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/

Y80

Y40

Y20

Y10

MSB

LSB

Year data (00 to 99)

M10

MSB

LSB

Month data (01 to 12)

D20

D10

MSB

LSB

Day data (01 to 31)

MSB

LSB

Day of week data (00 to 06)

A septenary counter. Set it so that it corresponds to the day
of the week.

H20

H10

MSB

LSB

Hour data (00 to 23 or 00 to 11)

MSB

LSB

Minute data (00 to 59)

TE
ST

S40

S20

S10

MSB

LSB

Second data (00 to 59) and test flag

m10

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.

Figure 6

Real-time data register

m20

m40

Real-Time Clock

S-3511A

Seiko Instruments Inc.

2-2. Status register

The status register is an eight-bit register which allows you to display and set various modes. The POWER flag is read-only

and others are read/write-enabled.

B7:POWER

This flag turns to "1" if the power voltage detecting circuit operates during power-on or changes in power

voltage (below VDET). Once turning to "1", this flag does not turns back to "0" even when the power

voltage reaches or exceeds the detected voltage. When the flag is "1", you must send the reset 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:INTAE

This flag is used to choose the state of INT terminal output with interrupt output set. Enable this flag after

setting alarm time that forms a meeting condition in the INT register:

0 : Alarm interrupt output is disabled.

1 : Alarm interrupt output is enabled.

B3:INTME

This flag is used to make the output of the INT terminal per-minute edge interrupt or per-minute steady

interrupt. To make the output per-minute steady interrupt, set "1" at INTME and INTFE .

0 : Alarm interrupt or selected frequency steady interrupt output

1 : Per-minute edge interrupt or per-minute steady interrupt output

B1:INTFE

This flag is used to make the output of the INT terminal per-minute steady interrupt output (a period of one

minute, 50% of duty) or selected frequency steady interrupt. Note that the INT register is considered as the

data of frequency/duty if selected frequency steady interrupt is chosen.

0 : Alarm interrupt or selected frequency steady interrupt output

1 : Per-minute edge interrupt or per-minute steady interrupt output

B4, B2 and B0: If having written contents, they are ignored. When they are read, "0" can be read from them.

LSB

POWER

12/24

INTAE

R/W

�

INTME

MSB

�

INTFE

�

Figure 7 Status register

Real-Time Clock
S-3511A

Seiko Instruments Inc.

2-3. Alarm time/Frequency duty setting register

The alarm time/frequency duty setting register is a sixteen-bit register which sets alarm time or frequency duty. They are

switched by INTAE or INTFE register. AM/PM flag to be set must be in accordance with 12-hour or 24-hour expression. If

AM/PM flag is not rightly then set hour data is not met to alarm data.The alarm time/frequency duty setting register is a

write-only register.

(1)

When INTAE = 1

INT register is considered as alarm time data. Having the same configuration as the time and minutes registers of real-time

day. Data to be set must be in accordance with 12-hour or 24-hour expression that is set at the status register.

(2) When INTFE = 1

INT register is considered as frequency duty data. By turning each bit of the registers to "1", a frequency corresponding to

each bit is chosen in an ANDed form.

AM/
PM

MSB

LSB

INT register

MSB

LSB

H20

H10

Figure 8 INT register (alarm)

m10

m20

m40

MSB

LSB

INT register

MSB

LSB

f10

f11

f12

f13

f14

f15

32768HZ

f10

f11

f12

f13

f14

f15

16384HZ

8192HZ

4096HZ

2048HZ

1024HZ

512HZ

256HZ

128HZ

8HZ

4HZ

2HZ

1HZ

64HZ

32HZ

16HZ

Figure 9 INT register (frequency duty)

Real-Time Clock

S-3511A

Seiko Instruments Inc.

2-4. Test flag

The test flag is a one-bit register which is assigned to MSB of the second data of the real-time data register. If a transferred

data is considered as the test mode starting data due to the receiving of the test mode starting data or noises, "1" is set.

When "1" is set, you must send the test mode ending command or reset command.

Initialization

Note that S-3511A has different initializing operations, depending on states.

3-1. When power is turned on

Real-time data register :

00 (year), 01 (month), 01 (day), 0 (day of week), 00 (hour), 00 (minute), 00 (second)

Status register

"82h"

INT register

"8000h"

3-2. When the power voltage detecting circuits operates

The power voltage detecting circuit included in S-3511A 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 detected power voltage. 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-3511A does not reach any indefinite area during

backup), you do not have to send the reset command.

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"

INT register

"0000h"

32KHZ

Example

If f15 to f0 = 000AH

16KHZ

8KHZ

4KHZ

2KHZ

INT terminal output

Figure 10 Clock output

Set to frequency
duty mode

When power is turned on, the status register is set to "82h" and the INT register to "8000h" by the power-on detecting

circuit. In other words, "1" is sets at the bit 7 (POWER flag) of the status register and the clock of 1HZ is output from the INT

terminal. This is provided to adjust oscillating frequencies. In normal use, the reset command must be sent when power is

turned on.

Real-Time Clock
S-3511A

Seiko Instruments Inc.

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 3 None-existent data processing

[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.

Normal data

Error data

Result

Year data

00 to 99

XA to XF, AX to FX

Month data

01 to 12

00, 13 to 19, XA to XF

Day data

01 to 31

00, 32 to 39, XA to XF

Day of week data

0 to 6

Hour data (24-hour)

(*)

(12-hour)

0 to 23

0 to 11

24 to 29, 3X, XA to XF

12 to 19, XA to XF

Minute data

00 to 59

60 to 79, XA to XF

Second data (**)

00 to 59

60 to 79, XA to XF

Figure 11

Initializing

1 1

S
B

SIO LINE

0 0

S
B

command

status access command

VDD

POWER

flag

1 1

S
B

SIO LINE

0 0

S
B

command

VDD

POWER

flag

S
B

0 0

S
B

0 0

0 0 0

POWER flag

Don't care

backup state (S-3511A does not reach any indefinite area)

1 1

S
B

0 1

S
B

0 0

0 0 0

POWER flag

CPU down

reset command

status data

data

status access command

status data

command

real-time data access command

(*)

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.

(**) 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.

Real-Time Clock

S-3511A

Seiko Instruments Inc.

Interrupt

Note 1 : If changing an output mode, give care to the state of the INT register and output.

Note 2 : If per-minute edge interrupt output or per-minute steady interrupt output is chosen, the INT register have no meaning.

NO.

INTAE

INTME

INTFE

Description

Output disabled

Selected frequency steady interrupt output

Per-minute edge interrupt output

Per-minute steady interrupt output

Alarm interrupt output

Note * : Don't care.

Table 4 Interrupt description

There are five types of output format from the INT terminal, which are selected by the INTAE, INTME and INTFE bits of the

status register.

(1) Alarm interrupt output

Alarm interrupt is enabled by setting hour and minute data to the INT register and turning the status register's INTAE to "1"

and INTME and INTFE to "0". When set hour data is met, low is output from the INT terminal. Since the output is held,

rewrite INTAE of the status register to "0" through serial communication to turn the output to high (OFF state).

(2) Selected frequency steady interrupt output

When you set frequency/duty data to the INT register and turn the status register's INTME to "0" and INTFE to "1" , clock set

at the INT register is output from the INT terminal.

(3) Per-minute edge interrupt output

When a first minute carry is performed after the status register's INTME is set with "1" and INTFE with "0", low is output from

the INT terminal. Since the output is held, rewrite INTAE, INTME and INTFE of the status register through a serial

communication. When you perform DISABLE or ENABLE communication while the minute carry processing signal is being

retained (for 10 msec), "Low" signal is output from the INT terminal again.

(4) Per-minute steady interrupt output

When a first carry is performed after the status register's INTME and INTFE are set with "1" , clock is output from the INT

terminal with a period of one minute (50% duty). When you perform DISABLE or ENABLE communication while the INT

terminal is at "L", "Low" signal is output from the INT terminal again.

Real-Time Clock
S-3511A

Seiko Instruments Inc.

Figure 12 Output mode

INTAE

INT terminal

INTME=INTFE=0

Alarm time corresponds

change by program

(1) Alarm interrupt output

INTFE

INT terminal

INTAE=INTME=0

Free run output starts

change by program

(2) Selected frequency steady interrupt output

INTME

INT terminal

INTAE=INTFE=0

(3) Per-minute edge interrupt output

INTFE,INTME

INT terminal

INTAE=0

(4) Per-minute steady interrupt output

OFF

INTFE

INT terminal

INTAE=INTME=0

Change by the reset command

(5 ) During power-on detecting circuit operation

OFF

0.5 second 0.5 second

OFF

"Low" signal is output again in case of

10 mSEC or less

Minute-carry processing

Change by program

OFF

Change by program

Minute-carry

processing

Minute-carry processing

Minute-carry

processing

30 seconds

Real-Time Clock

S-3511A

Seiko Instruments Inc.

Power voltage detecting circuit

S-3511A has an internal power voltage detecting circuit. This circuit gives sampling movement for only 15.6msec. once a second.

If the power voltage decreases below the detected voltage (VDET), 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.

[Note]

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)

1sec

Stop

(1)

(1) (1)

(0)

VDD

POWER flag

DET

Communication

Sampling pulse

Carry pulse

1sec

(1)

(0)

Latch circuit
output

POWER flag

[Timing of sampling pulse]

0.5sec

7.8mse

Carry-up timing

15.6mse

Latch timing

1Hz

DET

Sampling pulse

Stop

(1)

(0)

Figure 13 Timing of the power voltage detecting circuit

VDD

Real-Time Clock
S-3511A

Seiko Instruments Inc.

Example of software treatment

(1 ) Initialization flow at power-on

YES

START

END

POWER=1

(*1) If S-3511 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 alternately

Power on

Reset command

transfer

YES

TEST=1

Reset command

transfer

Status register setting

command transfer

Real-time data setting

command transfer

INT register setting

command transfer

(*1)

(*2)

(*3)

Figure 14 Initialization flow

Real-Time Clock

S-3511A

Seiko Instruments Inc.

Samples of Applied Circuits

Vcc

OUT

S-3511AEFS

SIO

Vss

SCK

Vss

Vcc

External CPU

INT

System
power

Due to the I/O terminal 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 15 Applied circuit 1

Make communications after the system power is turned on and a stable state is obtained.

Vss

Vcc

External CPU

Power
switching
circuit

OUT

S-3511AEFS

Vss

System
power

Figure 16 Applied circuit 2

INT

SIO

SCK

Real-Time Clock

S-3511A

Seiko Instruments Inc.

Adjustment of Oscillating Frequency

Configuration of the oscillating circuit

Since crystal oscillation is sensitive to external noises (clock accuracy is affected), the fallowing measures must be taken in configuring

the oscillating circuit:

(1) S-3511A, crystal oscillator and external capacitor (Cg) are placed as close to each other as possible.

(2) Make high the insulation resistance between terminals and the board between XIN and XOUT.

(3) Do not place any signal or power lines close to the oscillating circuit.

Measurement of oscillating frequencies

(*) If the error range is �1ppm in relation to 1HZ, time is shifted by approximately 2.6 seconds a month:

-6(1ppm)

60 seconds

60 minutes

24 hours

30 days = 2.592 seconds

XIN

XOUT

S-3511A

Figure 18 Connection diagram

Crystal oscillator:32.768KHZ

CL=6pf
Cg=3 to 35pf

Oscillating circuit internal constant standard values:

Rf=20M

Rd=220K

Cd=12pf

When power is turned on, S-3511A has the internal power-on detecting circuit operating and outputs a signal of 1HZ from the INT

terminal to select the crystal oscillator and optimize the Cg value. Turn power on and measure the signal with a frequency counter

following the circuit configuration shown in Figure 22. Refer to 9 and 12 pages in this document for further information.

INT

Frequency
counter

VDD

XIN

XOUT

SIO

VSS

SCK

Open

S-3511A

Note 1: Use a high-accuracy frequency

counter (1ppm order).

Note 2: Since the 1HZ signal continues

to be output, you must send the
reset command in normal
operation.

Note 3: Determine Cg with its

frequency slow/fast range
property referred.

Figure 19 Connection diagram

Real-Time Clock
S-3511A

Seiko Instruments Inc.

Adjustment of oscillating frequencies

Matching of a crystal oscillator with the nominal frequency must be performed with suspended capacity on the board included. Select a

crystal oscillator and optimize the Cg value in accordance with the flow chart below.

(*1)

For making matching adjustment of the IC with a crystal, contact an appropriate crystal maker to determine the CL value

(load capacity) and RI value (equivalent serial capacity). The CL value = 6pf and RI value = 30K

TYP. are recommended

values.

(*2)

Cg value selection must be performed on the actual PCB since suspended capacity affects it. Select the Cg value in a

range from 3pf to 35pf. If the frequency does not match, change the CL 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 CL value of the crystal.

Note 1 : Oscillating frequencies are changed by ambient temperature and power voltage. Refer to property samples.

Note 2 : The 32KHZ 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.

YES

START

Variable
capacity

Select a crystal oscillator.

Is Cg in the

specification

(*1)

(*2)

Cg set

Is it an

optimal
value ?

YES

Change Cg.

END

YES

Set to the center of

variable capacitor.

Does

the frequency

match ?

YES

Make fine adjustment of the

frequency in variable capacity.

(*3)

Real-Time Clock

S-3511A

Seiko Instruments Inc.

Absolute Maximum Ratings

Table 5 Absolute maximum ratings

Item

Symbol

Rating

Unit

Applicable terminal,

conditions

Power voltage

VDD

�0.3 to +6.5

Input voltage

�0.3 to +6.5

SCK, SIO

Output voltage

OUT

�0.3 to +6.5

SIO, INT

Operating temperature

opr

�40 to +85

�C

VDD=3.0V

Retention temperature

stg

�55 to + 25

�C

Recommended Operating Conditions

Table 6 Recommended operating conditions

Item

Symbol

Condition

Min.

Typ.

Max.

Unit

Power voltage

VDD

1.7

3.0

5.5

Operating temperature

opr

�20

+25

+70

�C

Oscillation Characteristics

Table 7 Oscillation characteristics

(Ta=25�C, VDD=3V, DS-VT-200 (crystal oscillator, CL=6pF, 32,768HZ) manufactured by Seiko Electronic Part Co., Ltd.)

Item

Symbol

Condition

Min.

Typ.

Max.

Unit

Oscillation start voltage

STA

Within ten seconds

1.7

5.5

Oscillation start time

STA

SEC

IC-to-IC frequency diversity

�10

+10

ppm

Frequency voltage
diversity

VDD=1.7 to 5.5V

�3

ppm/V

Input capacity

Applied to the XIN terminal

Output capacity

Applied to the XOUT terminal

---

Real-Time Clock
S-3511A

Seiko Instruments Inc.

DC Electrical Characteristics

Table 8 DC characteristics (3V)

Item

Symbol

Condition

Min.

Typ.

Max.

Unit

Applicable

terminal

Range of operating
voltage

VDD

Ta = �20 to+70�C

1.7

3.0

5.5

Drain current 1

DD1

During no
communications

0.7

1.5

Drain current 2

DD2

During
communications
(SCL=100KHZ)

5.5

Input leak current 1

ILL1

= VDD

�0.5

0.5

SCK,SIO

Input leak current 2

ILL2

= VSS

�0.5

0.5

SCK,SIO

Input current 1

IL1

=5.5V

Input current 2

IL2

=0.4V

110

300

Output leak current1

OZH

OUT

=VDD

�0.5

0.5

INT, SIO

Output leak current2

OZL

OUT

=VSS

�0.5

0.5

INT, SIO

Input voltage 1

0.8xVDD

SIO, SCK, CS

Input voltage 2

0.2xVDD

SIO, SCK, CS

Output current 1

OL1

OUT

=0.4V

1.5

2.5

INT

Output current 2

OL2

OUT

=0.4V

SIO

Power voltage detecting
voltage 1

DET1

Ta=+25�C

1.8

2.0

2.2

Power voltage detecting
voltage 2

DET2

Ta= �20 to+70�C

1.72

2.3

(Ta=25�C,VDD=3V,DS-VT-200 (crystal oscillator, CL=6pF, 32,768HZ) manufactured by Seiko Electronic Part Co., Ltd.)

Real-Time Clock

S-3511A

Seiko Instruments Inc.

Table 9 DC characteristics (5V)

Item

Symbol

Condition

Min.

Typ.

Max.

Unit

Applicable

terminal

Range of operating
voltage

VDD

Ta = �20 to+70�C

1.7

3.0

5.5

Drain current 1

DD1

During no
communications

1.6

3.0

Drain current 2

DD2

During
communications
(SCL=100KHZ)

Input leak current 1

ILL1

= VDD

� 0.5

0.5

SCK,SIO

Input leak current 2

ILL2

= VSS

� 0.5

0.5

SCK,SIO

Input current 1

IL1

=5.5V

Input current 2

IL2

=0.4V

100

175

400

Output leak current1

OZH

OUT

=VDD

� 0.5

0.5

INT, SIO

Output leak current2

OZL

OUT

=VSS

� 0.5

0.5

INT, SIO

Input voltage 1

0.8xVDD

SIO, SCK, CS

Input voltage 2

0.2xVDD

SIO, SCK, CS

Output current 1

OL1

OUT

=0.4V

2.0

3.5

INT

Output current 2

OL2

OUT

=0.4V

SIO

Power voltage detecting
voltage 1

DET1

Ta=+25�C

1.8

2.0

2.2

Power voltage detecting
voltage 2

DET2

Ta= �20 to+70�C

1.72

2.3

(Ta=25�C, VDD=3V, DS-VT-200 (crystal oscillator, CL=6pF, 32,768HZ) manufactured by Seiko Electronic Part Co., Ltd.)

Real-Time Clock
S-3511A

Seiko Instruments Inc.

AC Electrical Characteristics

Table 10 AC characteristics 1

(S-3511A, RL=10K

, CL=80pF)

Conditions: VDD = 1.7V to 5.5V, Ta = �20 to 70�C

Input; V

=0.8

VDD, V

=0.2

VDD, Output; V

=0.8

VDD, V

=0.2

VDD

Item

Symbol

Min.

Typ.

Max.

Unit

Clock pulse width

SCK

250000

Setup time before CS rising

Hold time after CS rising

CSH

Input data setup time

ISU

Input data hold time

IHO

Output data definition time

ACC

3.5

Setup time before CS falling

CSS

Hold time after CS falling

Input rising/falling time

0.1

Note:

Since the output form of the SIO terminal is N-channel open drain output, the rising time of t

ACC

determined by the values of load resistance (RL) and load capacity (CL) outside the IC. Use this as

a reference value.

Table 11

AC characteristics 2

(S-3511A, RL=10K

, CL=80pF)

Conditions ; VDD=3.0

0.3V, Ta=-20~70�C

Input ; V

=0.8

VDD, V

=0.2

VDD, Output ; V

=0.8

VCC, V

=0.2

VCC(VCC=5.0V)

Item

Symbol

Min.

Typ.

Max.

Unit

Clock pulse width

SCK

250000

Setup time before CS rising

0.2

Hold time after CS rising

CSH

0.2

Input data setup time

ISU

0.2

Input data hold time

IHO

0.2

Output data definition time

ACC

1.0

Setup time before CS falling

CSS

0.2

Hold time after CS falling

0.2

Input rising/falling time

0.05

Note:

Since the output form of the SIO terminal is N-channel open drain output, the rising time of t

ACC

determined by the values of load resistance (RL) and load capacity (CL) outside the IC. Use this as

a reference value

Real-Time Clock

S-3511A

Seiko Instruments Inc.

Table 12

AC characteristics 3

(S-3511A,RL=10K

, C

=80pF)

Conditions: VDD=5.0

0.5V, Ta=-20 to 70�C

Input; V

=0.8

VDD, V

=0.2

VDD, Output; V

=0.8

VDD, V

=0.2

VDD

Item

Symbol

Min.

Typ.

Max.

Unit

Clock pulse width

SCK

0.5

250000

Setup time before CS rising

0.1

Hold time after CS rising

CSH

0.1

Input data setup time

ISU

0.1

Input data hold time

IHO

0.1

Output data definition time

ACC

0.3

Setup time before CS falling

CSS

0.1

Hold time after CS falling

0.1

Input rising/falling time

0.05

Note:

Since the output form of the SIO terminal is N-channel open drain output, the rising time of t

ACC

determined by the values of load resistance (RL) and load capacity (CL) outside the IC. Use this as

a reference value.

Real-Time Clock

S-3511A

Seiko Instruments Inc.

Sample of Properties (Reference values)

(1) Standby current versus Cg

Ta=25�C

(2) Standby current versus VDD

Ta=25�C

(3) Operating drain current versus Input clock

Ta=25�C

(4) Standby current versus temperature

(5) Oscillating frequency versus Cg

Ta=25�C

(6) Oscillating frequency versus VDD

SCK frequency

0.5

1.5

[pf]

IDD1

[uA]

0.5

1.5

2.5

IDD1

[uA]

VDD

[V]

[�C]

-30

-10

0.5

1.5

IDD1

[uA]

400

1,000

100

150

IDD2

[uA]

Ta=25�C

VDD

[V]

-4

-2

f/f

[ppm]

[pf]

f/f

[ppm]

-20

VDD=5V

VDD=3V

VDD=5V

VDD=3V

VDD=5V

VDD=3V

VDD=5V

Real-Time Clock
S-3511A

Seiko Instruments Inc.

(8) Oscillation start time versus Cg

(9) Output current 1 (VDS versus IDS)

INT terminals,Ta=25

�C

(7) Oscillating frequency versus temperature

(10) Output current 2 (VDS versus IDS)

SIO terminal,Ta=25

�C

Ta=25

�C

[pf]

STA

[mS]

200

400

600

800

-50

100

-160

-120

-80

-40

Ta=25

�C,VDD=3V

[�C]

f/f

[ppm]

VDS

[V]

IDS

[mA]

VDS

[V]

IDS

[mA]

VDD=5V

VDD=3V

VDD=5V

VDD=3V

VDD=5V

VDD=3V

Collection of Product FAQs

Author: Shirai Masaaki

Date: 99/04/16 (Friday) 18:20 (modified: 99/04/16(Friday))

Public (Printing O.K.)

Index:

B: General

Division name: 01 IC

Category 1:

17 ASSP

Category 2:

2. Real-Time Clock

Product name: Overall

Related documents:

Question:

What are the notes for time settings (S3511/S3530/S3531)?

Answer:

If time data is rewritten in a product with an alarm interrupt (S-3511/S-3530/S-3531), be sure to disable

the alarm interrupt before the time is set.

Reason: When data is written using real-time data access 2, registers for hours, minutes, and seconds

are reset (all "0"'s), and arbitrary hours, minutes, and seconds are then set. If the alarm is set for 0:00

a.m. and the alarm interrupt is enabled, when the time data is rewritten the registers are reset (all "0"'s)

to 0:00 a.m., the set alarm time, thereby causing an interrupt (INT).

FAQ No.: 17S35004

Collection of Product FAQs

Author: Shirai Masaaki

Date: 99/04/14 (Wednesday) 11:34 (modified: 99/05/18)

Public (Printing O.K.)

Index:

B: Technical

Division name: 01 IC

Category 1:

17 ASSP

Category 2:

2. Real-Time Clock

Cal No.:

Overall

Related documents:

Question:

What about the write/read errors (notes)?

Answer:

To continuously write or read data in a 3-wire RTC (S-3511/S-3513/S-35L12/S-3510), be sure to change

"CS" to "L" after the first command has been executed and before the next command is executed. If

commands are continuously executed without changing "CS" to "L," the second command is

disregarded.

Be sure to change
"CS" to "L."

SCK

SIO

Status data

LSB

MSB

Command

MSB

LSB

POWER

Time data

LSB

MSB

Command

MSB

LSB

FAQ No.: 17S35003

Collection of Product FAQs

Author: Shirai Masaaki

Date: 99/04/13 (Tuesday) 15:40 (modified: 99/05/18)

Public (Printing O.K.)

Index:

A: General

Division name: 01 IC

Category 1:

17 ASSP

Category 2:

2. Real-Time Clock

Cal No.:

Overall

Related documents:

Question:

What about the Y2K problem?

Answer:

Our Real-Time Clock outputs information consisting of the last two digits of the year. The S-35L12/L32

can use the register bits in its RTC to determine whether the year is 1900 or 2000 when the last two

digits change from 99 to 00. Most other RTCs, however, cannot determine whether the year is 1900 or

2000 when the last two digits change from 99 to 00. Thus, when this microcomputer is used, the user

must load year information for the RTC in a microcomputer to determine whether the year is 1900 or

2000. Accordingly, when the year reaches 2000, our RTC allows year information to operate normally

and be output as "00," thereby preventing malfunctions.

There is no problem with the operation of the IC. If, however, peripheral circuits and software

developed by a client manage year information using the last two digits of the year, they may

malfunction. Thus, such devices should be checked.

http://www.sii.co.jp/sii2000.htm

FAQ No.: 17S35002

Collection of Product FAQs

Author: Shirai Masaaki

Date: 99/04/13 (Tuesday) 14:26 (modified: 99/04/13)

Public (Printing O.K.)

Index:

A: General

Division name: 01 IC

Category 1:

17 ASSP

Category 2:

2. Real-Time Clock

Cal No.:

Overall

Related documents:

Question:

Why is an auto calendar available through the year 2099?

Answer:

The SII's RTC denotes the year using its last two digits. These digits are then divided by four, and if

they are divisible the year is determined to be a leap year (the auto calendar determines both 1996 and

2000 to be leap years). The actual calendar, however, does not treat a year with "00" as its last two

digits as a leap year (except for the year 2000; see the following). Accordingly, although 2100 is not a

leap year, the RTC treats it as one. Therefore, this auto calendar is available through 2099.

(Note) A year is defined as a leap year when its last two digits are "00" and its first two digits are

divisible by four.

FAQ No.: 17S35001

Электронный компонент: S-3511A