Rainbow Electronics DS1337 User Manual

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A

www.maxim-ic.com

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 through an

2

I

C™ 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, Switch, Server)

Other (Utility Meter, Vending Machine, Thermostat,

Modem)

TYPICAL OPERATING CIRCUIT

V

CC

V

CC

RPU

RPU

CRYSTAL

V

CC

i

DS1337

2

C Serial Real-Time Clock

I

FEATURES

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

§ Available in a Surface-Mount Package with an
Integrated Crystal (DS1337C)

2

§ I

C 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 (300 mils) DS1337

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

DS1337U -40°C to +85°C
DS1337C -40°C to +85°C 16 SO (300 mils) DS1337C

Pin Configurations appear at end of data sheet.

8 mSOP

TOP

MARK

1337

V

X2 X1

SCL

CPU

RPU = tR / CB

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, go to: www.maxim-ic.com/errata

DS1337

SDA

GND

CC

SQW/INT

INT

i

i

I2C is a trademark of Philips Corp. Purchase of I2C components from
Maxim Integrated Products, Inc., or one of its sublicensed Associated
Companies, conveys a license under the Philips I
use these components in an I
conforms to the I

2

C Standard Specification as defined by Philips.

2

C system, provided that the system

2

C Patent Rights to

.

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REV: 091404

DS1337 I2C Serial Real-Time Clock

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…………………..See precautions in the Handling, PC Board Layout, and Assembly section.

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 reliability.

RECOMMENDED DC OPERATING CONDITIONS

(TA = -40°C to +85°C)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Supply Voltage

VCC 1.8 5.5 V

V

1.3 5.5 V

OSC

Logic 1 VIH

Logic 0 VIL

SCL, SDA 0.7 x VCC VCC + 0.3

INTA, SQW/INTB

-0.3 +0.3 x V

5.5

CC

V

V

DC ELECTRICAL CHARACTERISTICS

(VCC = 1.8V to 5.5V, TA = -40°C to +85°C.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Input Leakage ILI (Note 2) -1 +1

I/O Leakage ILO (Note 3) -1 +1

Logic 0 Output (VOL = 0.4V) IOL (Note 3) 3 mA

Active Supply Current I

Standby Current I

(Note 4) 150

CCA

(Notes 5, 6) 1.5

CCS

mA

mA

mA

mA

DC ELECTRICAL CHARACTERISTICS

(VCC = 1.3V to 1.8V, TA = -40°C to +85°C.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Timekeeping Current
(Oscillator Enabled)

Data-Retention Current
(Oscillator Disabled)

I

(Notes 5, 7, 8, 9) 600 nA

OSC

I

(Note 5) 50 nA

DDR

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AC ELECTRICAL CHARACTERISTICS

(VCC = 1.8V to 5.5V, TA = -40°C to +85°C.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DS1337 I2C Serial Real-Time Clock

SCL Clock Frequency f

Bus Free Time Between a
STOP and START Condition

Hold Time (Repeated)
START Condition (Note 10)

t

LOW Period of SCL Clock t

HIGH Period of SCL Clock t

Setup Time for a Repeated
START Condition

(Notes 11, 12)

t

t

Data Setup Time (Note 13) t

Rise Time of Both SDA and
SCL Signals (Note 14)

Fall Time of Both SDA and
SCL Signals (Note 14)

Setup Time for STOP
Condition

t

Capacitive Load for Each Bus
Line

Fast mode 100 400

t

SCL

BUF

Standard mode 100
Fast mode 1.3

Standard mode 4.7

kHz

Fast mode 0.6

HD:STA

LOW

HIGH

SU:STA

HD:DAT

SU:DAT

t

R

t

F

SU:STO

C

B

Standard mode 4.0

Fast mode 1.3

Standard mode 4.7

Fast mode 0.6
Standard mode 4.0
Fast mode 0.6
Standard mode 4.7
Fast mode 0 0.9 Data Hold Time

Standard mode 0
Fast mode 100
Standard mode 250
Fast mode 20 + 0.1CB 300
Standard mode 20 + 0.1CB 1000
Fast mode 20 + 0.1CB 300

Standard mode 20 + 0.1C
Fast mode 0.6
Standard mode 4.0

300

B

(Note 14) 400 pF

ms

ms

ms

ms

ms

ms

ns

ns

ns

ms

I/O Capacitance (SDA, SCL) C

Note 1:

Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Note 9:

Note 10:

Note 11:

Note 12:

Note 13:

Note 14:

Note 15:

Limits at -40°C are guaranteed by design and are not production tested.
SCL only.
SDA, INTA, and SQW/INTB.

I

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

CCA

Specified with the I2C bus inactive, VIL = 0.0V, VIH = V
SQW enabled.
Specified with the SQW function disabled by setting INTCN = 1.
Using recommended crystal on X1 and X2.

The device is fully accessible when 1.8 £ VCC £ 5.5V. Time and date are maintained when 1.3V £ VCC £ 1.8V.

After this period, the first clock pulse is generated

A device must internally provide a hold time of at least 300ns for the SDA signal (referred to the V
bridge the undefined region of the falling edge of SCL.

The maximum t

A fast-mode device can be used in a standard-mode system, but the requirement t
automatically 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
line is released.

C

—total capacitance of one bus line in pF.

B

Guaranteed by design. Not production tested.

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

HD:DAT

(Note 15) 10 pF

I/O

CC.

CC.

of the SCL signal) to

IHMIN

) of the SCL signal.

LOW

³ to 250ns must then be met. This is

SU:DAT

R max + tSU:DAT

= 1000 + 250 = 1250ns before the SCL

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TYPICAL OPERATING CHARACTERISTICS

I

VS. V

500

(SQUARE-WAVE OFF)

450

400

SUPPLY CURRENT (nA)

350

300

1.8

1.3

OSC

2.3

2.8

VCC (V)

CC

DS1337 toc01

3.3

4.3

3.8

4.8

850

800

750

700

650

600

550

500

SUPPLY CURRENT (nA)

450

400

350

1.8

1.3

DS1337 I2C Serial Real-Time Clock

I

VS. V

OSC

(SQUARE-WAVE ON)

VCC (V)

CC

DS1337 toc02

3.8

3.32.3 2.8

4.84.3

I

OSC

(SQUARE-WAVE OFF)

475

450

425

SUPPLY CURRENT (nA)

375

350

-40

VS. TEMPERATURE

VCC = 3.0V

TEMPERATURE (°C)

32767.75

32767.70

32767.65

32767.60

FREQUENCY (Hz)

32767.55

DS1337 toc03

806040200-20

60

40

20

SUPPLY CURRENT (µA)

0

1.8 5.3

OSCILLATOR FREQUENCY vs. V

VCC = 0V

I

vs. V

CCA

(SQUARE-WAVE ON)

VCC (V)

CC

DS1337 toc05

CC

DS1337 toc04

4.84.33.3 3.82.82.3

32767.50

32767.45

1.3 4.8
VCC (V)

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4.33.83.32.82.31.8

PIN DESCRIPTION

PIN

8 16

1 — X1

2 — X2

3 14

4 15 GND DC power is provided to the device on these pins.

5 16 SDA

6 1 SCL

7 2

8 3 VCC DC power is provided to the device on these pins.

NAME FUNCTION

Connections for a Standard 32.768kHz Quartz Crystal. The internal
oscillator circuitry is designed for operation with a crystal having a specified

INTA

SQW/

INTB

load capacitance (C
and crystal layout considerations, refer to Application Note 58: Crystal
Considerations with Dallas Real-Time Clocks. An external 32.768kHz
oscillator can also drive the DS1337. In this configuration, the X1 pin is
connected to the external oscillator signal and the X2 pin is floated.

Interrupt Output. When enabled, INTA is asserted low when the
time/day/date matches the values set in the alarm registers. This pin is an
open-drain output and requires an external pullup resistor.

Serial Data Input/Output. SDA is the input/output pin for the I
interface. The SDA pin is open-drain output and requires an external pullup
resistor.

Serial Clock Input. SCL is used to synchronize data movement on the serial
interface.

Square-Wave/Interrupt Output. Programmable square-wave or interrupt
output signal. It is an open-drain output and requires an external pullup
resistor.

) of 6pF. For more information about crystal selection

L

DS1337 I2C Serial Real-Time Clock

2

C serial

— 4–13 N.C.

TIMING DIAGRAM

No Connect. These pins are not connected internally, but must be
grounded for proper operation.

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