Dallas Semiconductor DS1337U, DS1337S, DS1337 Datasheet

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GENERAL DESCRIPTION

The DS1337 serial real-time clock is a low-power
clock/calendar with two programmable time-of-day
alarms and a programmable square-wave output.
Address and data are transferred serially via a 2-wire,
bidirectional bus. The clock/calendar provides
seconds, minutes, hours, day, date, month, and year
information. The date at the end of the month is
automatically adjusted for months with fewer than 31
days, including corrections for leap year. The clock
operates in either the 24-hour or 12-hour format with
AM/PM indicator.

APPLICATIONS

Handhelds (GPS, POS Terminal, MP3 Player)
Consumer Electronics (Set-Top Box, VCR/Digital

Recording)
Office Equipment (Fax/Printer, Copier)
Medical (Glucometer, Medicine Dispenser)
Telecommunications (Router, Switcher, Server)
Other (Utility Meter, Vending Machine, Thermostat,

Modem)

TYPICAL OPERATING CIRCUIT

DS1337

Serial Real-Time Clock

FEATURES

§ Real-Time Clock (RTC) Counts Seconds,
Minutes, Hours, Day, Date, Month, and Year
with Leap-Year Compensation Valid Up to 2100

§ Two-Wire Serial Interface

§ Two Time-of-Day Alarms

§ Oscillator Stop Flag

§ Programmable Square-Wave Output

– Defaults to 32kHz on Power-Up

§ Available in 8-Pin DIP, SO, or mSOP

ORDERING INFORMATION

PART TEMP RANGE PIN-PACKAGE

DS1337 -40°C to +85°C 8 DIP (300mil) DS1337

DS1337S -40°C to +85°C 8 SO (150mil) DS1337

DS1337U -40°C to +85°C

8 mSOP

PIN CONFIGURATIONS

TOP VIEW

X1

X2

GND

DS1337

X1

X2

INT

GND

DIP

DS1337

SO, mSOP

VCC

SQW/INTB

SCL

SDA

VCC

SCL

SDA

TOP
MARK

1337

Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device
may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata

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REV: 012003

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DS1337

ABSOLUTE MAXIMUM RATINGS

Voltage Range on Any Pin Relative to Ground -0.3V to +6.0V
Operating Temperature Range -40°C to +85°C
Storage Temperature Range -55°C to +125°C
Soldering Temperature Range See IPC/JEDEC J-STD-020A Specification

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only,
and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is
not implied. Exposure to the absolute maximum rating conditions for extended periods may affect device.

RECOMMENDED DC OPERATING CONDITIONS

(TA = -40°C to +85°C)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Supply Voltage VCC 1.8 4.0 V

Oscillator Voltage V

Logic 1 VIH

Logic 0 VIL

1.3 4.0 V

OSC

SCL, SDA 0.7 VCC VCC + 0.3

INTA, SQW/INTB

-0.3 0.3 V

5.5

CC

V

V

DC ELECTRICAL CHARACTERISTICS

(VCC = 1.8V to 4.0V, TA = -40°C to +85°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Input Leakage ILI
I/O Leakage ILO
Logic 0 Output (VOL = 0.4V) IOL (Note 2) 3 mA
Active Supply Current I
Standby Current I

CCA

CCS

(Note 1) 1
(Note 2) 1

(Note 3) 150
(Notes 4, 5) 2

mA
mA

mA
mA

DC ELECTRICAL CHARACTERISTICS

(VCC = 1.3V to 1.8V, TA = -40°C to +85°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Timekeeping Current
(Oscillator Enabled)
Data Retention Current
(Oscillator Disabled)

I

(Notes 4, 6, 7) 600 nA

OSC

I

(Note 4) 50 nA

DDR

CRYSTAL SPECIFICATIONS*

PARAMETER SYMBOL MIN TYP MAX UNITS

Nominal Frequency FO 32.768 kHz
Series Resistance ESR 45 kΩ
Load Capacitance CL 6 pF

*The crystal, traces, and crystal input pins should be isolated from RF generating signals. Refer to Application Note 58: Crystal Considerations
for Dallas Real-Time Clocks for additional specifications.

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AC ELECTRICAL CHARACTERISTICS

(VCC = 1.8V to 4.0V, TA = -40°C to +85°C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DS1337

SCL Clock Frequency f

Bus Free Time Between a
STOP and START Condition

Hold Time (Repeated)
START Condition (Note 8)

t

LOW Period of SCL Clock t

HIGH Period of SCL Clock t

Setup Time for a Repeated
START Condition

t

Data Hold Time (Notes 9, 10) t

Data Setup Time (Note 11) t

Rise Time of Both SDA and
SCL Signals (Note 12)

Fall Time of Both SDA and
SCL Signals (Note 12)

Condition

t

Capacitive Load for Each Bus
Line

SCL

Standard mode 100

kHz

Fast mode 100 400

Fast mode 1.3

t

BUF

Standard mode 4.7

Fast mode 0.6

HD:STA

LOW

HIGH

Standard mode 4.0

Fast mode 1.3

Standard mode 4.7
Fast mode 0.6

Standard mode 4.0
Fast mode 0.6

SU:STA

HD:DAT

SU:DAT

Standard mode 4.7

Fast mode 0 0.9
Standard mode 0
Fast mode 100
Standard mode 250

Fast mode 20 + 0.1CB 300

t

R

Standard mode 1000

Fast mode 20 + 0.1CB 300

t

F

SU:STO

C

B

Standard mode 300

Fast mode 0.6 Setup Time for STOP
Standard mode 4.0

(Note 12) 400 pF

ms

ms

ms

ms

ms

ms

ns

ns

ns

ms

I/O Capacitance C

Note 1: SCL only.
Note 2: SDA, INTA, and SQW/INTB.
Note 3: I
Note 4: Specified with 2-wire bus inactive, V
Note 5: SQW enabled.
Note 6: Specified with the SQW function disabled by setting INTCN = 1.
Note 7: Using recommended crystal on X1 and X2.
Note 8: After this period, the first clock pulse is generated.
Note 9: A device must internally provide a hold time of at least 300ns for the SDA signal (referred to the V

Note 10: The maximum t
Note 11: A fast-mode device can be used in a standard-mode system, but the requirement t

Note 12: C

—SCL clocking at max frequency = 400kHz, VIL = 0.0V, VIH = V

CCA

bridge the undefined region of the falling edge of SCL.

HD:DAT

automatically be the case if the device does not stretch the LOW period of the SCL signal. If such a device does stretch the LOW
period of the SCL signal, it must output the next data bit to the SDA line t
released.

—total capacitance of one bus line in pF.

B

has only to be met if the device does not stretch the LOW period (t

10 pF

I/O

= 0.0V, VIH = V

IL

CC.

CC.

R max + tSU:DAT

) of the SCL signal.

LOW

³ to 250ns must then be met. This is

SU:DAT

= 1000 + 250 = 1250ns before the SCL line is

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of the SCL signal) in order to

IHMIN

TYPICAL OPERATING CHARACTERISTICS

(VCC = 3.3V, TA = +25∞ C, unless otherwise noted.)

I

VS. V

500

(SQUARE-WAVE OFF)

450

400

SUPPLY CURRENT (nA)

350

300

1.3

OSC

CC

DS1337 toc01

4.84.33.83.32.31.8

V

(V)

BAT

850

800

750

700

650

600

550

500

SUPPLY CURRENT (nA)

450

400

350

I

VS. V

OSC

CC

(SQUARE-WAVE ON)

V

(V)

BAT

DS1337

DS1337 toc02

4.84.33.83.32.31.81.3

I

OSC

(SQUARE-WAVE OFF)

475

450

425

400

SUPPLY CURRENT (nA)

375

350

-40

VS. TEMPERATURE

VCC = 3.0V

TEMPERATURE ( C)

32767.75

32767.70

32767.65

275

DS1337 toc03

806040200-20

250

225

200

175

150

125

SUPPLY CURRENT (mA)

100

75

50

1.8 5.3

OSCILLATOR FREQUENCY vs. V

VCC = 0V

I

CCA

(SQUARE-WAVE ON)

VCC (V)

CC

DS1337 toc05

vs. V

CC

DS1337 toc04

4.84.33.3 3.82.82.3

32767.60

FREQUENCY (Hz)

32767.55

32767.50

32767.45

1.3 4.8
V

BACKUP

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4.33.83.32.82.31.8

(V)