Rainbow Electronics DS1338 User Manual

www.maxim-ic.com

GENERAL DESCRIPTION

The DS1338 serial real-time clock (RTC) is a lowpower, full binary-coded decimal (BCD) clock/calendar plus 56 bytes of NV SRAM. Address and data are transferred serially through an I

2

C™ interface. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The end of the month date 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. The DS1338 has a built-in powersense circuit that detects power failures and automatically switches to the battery supply.

APPLICATIONS

Handhelds (GPS, POS Terminal) Consumer Electronics (Set-Top Box, Digital

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

Modem)

TYPICAL OPERATING CIRCUIT

V

CPU

CC

RPU RPU

RPU = tR / CB

V

CC

CRYSTAL

SCL

X2 X1

V

CC

V

CC

SQW/OUT

i

DS1338

SDA

GND

V

BAT

DS1338

2

C RTC with 56-Byte NV RAM

I

FEATURES

§ RTC Counts Seconds, Minutes, Hours, Date of the Month, Month, Day of the Week, and Year with Leap-Year Compensation Valid Up to 2100

§ Available in a Surface-Mount Package with an Integrated Crystal (DS1338C)

§ 56-Byte Battery-Backed NV RAM for Data Storage

2

C Serial Interface

§ I

§ Programmable Square-Wave Output Signal

§ Automatic Power-Fail Detect and Switch Circuitry

§ Underwriters Laboratory (UL) Recognized

ORDERING INFORMATION

PART TEMP RANGE PIN-PACKAGE TOP MARK

DS1338Z-18 -40°C to +85°C 8 SO (150 mils) DS1338-18

DS1338Z-3 -40°C to +85°C 8 SO (150 mils) DS1338-3

DS1338Z-33 -40°C to +85°C 8 SO (150 mils) DS1338-33

DS1338U-18 -40°C to +85°C

DS1338U-3 -40°C to +85°C

DS1338U-33 -40°C to +85°C

DS1338C-18 -40°C to +85°C 16 SO (300 mils) DS1338C-18

DS1338C-3 -40°C to +85°C 16 SO (300 mils) DS1338C-3

DS1338C-33 -40°C to +85°C 16 SO (300 mils) DS1338C-33

rr = second line, revision level

Pin Configurations appear at end of data sheet.

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.

8 mSOP

2

C system, provided that the system

1338 rr-18 1338 rr-3 1338 rr-33

2

C Patent Rights to

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

.

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REV: 091404

DS1338 I2C RTC with 56-Byte NV RAM

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

(VCC = V

Supply Voltage VCC

Logic 1 VIH (Note 2) 0.7 x VCC V

Logic 0 VIL (Note 2) -0.3 +0.3 x V

Power-Fail Voltage VPF

V

Battery Voltage V

BAT

CC(MIN)

to V

, TA = -40°C to +85°C.) (Note 1)

CC(MAX)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DS1338-18 1.71 1.8 1.89 DS1338-3 2.7 3.0 3.3

V

DS1338-33 3.0 3.3 3.63

+ 0.3 V

CC

V

DS1338-18 1.51 1.62 1.71 DS1338-3 2.45 2.59 2.70

V

DS1338-33 2.70 2.82 2.97

(Note 2) 1.3 3.0 3.7 V

BAT

DC ELECTRICAL CHARACTERISTICS

(VCC = V

CC(MIN)

to V

, TA = -40°C to +85°C.) (Note 1)

CC(MAX)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

V

Battery Voltage V

BAT

(Note 2) 1.3 3.7 V

BAT

Input Leakage ILI (Note 3) 1

I/O Leakage ILO (Note 4) 1

SDA Logic 0 Output I

OLSDA

VCC > 2V; VOL = 0.4V 3.0

< 2V; VOL = 0.2 VCC 3.0

V

CC

VCC > 2V; VOL = 0.4V 3.0

SQW/OUT Logic 0 Output I

OLSQW

1.71V < VCC < 2V; = 0.2 VCC

V

OL

1.3V < V

V

= 0.2 VCC

OL

< 1.71V;

CC

3.0

250

DS1338-18 75 150

Active Supply Current (Note 5) I

CCA

DS1338-3 110 200 DS1338-33 120 200 DS1338-18 60 100

Standby Current (Note 6) I

CCS

DS1338-3 80 125 DS1338-33 85 125

V

Leakage Current

BAT

(V

Active)

CC

25 100 nA

I

BATLKG

mA

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DC ELECTRICAL CHARACTERISTICS

(VCC = 0V, TA = -40°C to +85°C.) (Note 1)

PARAMETER SYMBOL MIN TYP MAX UNITS

V

Current (OSC ON); V

BAT

V

Current (OSC ON); V

BAT

= 3.7V, SQW/OUT OFF (Note 7) I

BAT

= 3.7V, SQW/OUT ON (32kHz)

BAT

(Note 7)

V

Data-Retention Current (Osc Off); V

BAT

= 3.7V (Note 7) I

BAT

AC ELECTRICAL CHARACTERISTICS

(TA = -40°C to +85°C) (Note 1)

PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS

SCL Clock Frequency f

Bus Free Time Between STOP and START Condition

Hold Time (Repeated) START Condition (Note 8)

t

SCL

t

BUF

HD:STA

Fast mode 100 400

Standard mode 100

Fast mode 1.3

Standard mode 4.7

Fast mode 0.6

Standard mode 4.0

DS1338 I2C RTC with 56-Byte NV RAM

BATOSC1

I

BATOSC2

400 1200 nA

570 1400 nA

10 100 nA

BATDAT

kHz

ms

LOW Period of SCL Clock t

HIGH Period of SCL Clock t

Setup Time for Repeated START Condition

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)

Setup Time for STOP Condition

Capacitive Load for Each Bus Line

Fast mode 1.3

LOW

Standard mode 4.7

ms

Fast mode 0.6

HIGH

Standard mode 4.0

ms

Fast mode 0.6

t

SU:STA

Standard mode 4.7

ms

Fast mode 0 0.9

HD:DAT

Standard mode 0

ms

Fast mode 100

SU:DAT

Standard mode 250

ns

Fast mode 20 + 0.1CB 300

t

R

Standard mode 20 + 0.1CB 1000

ns

Fast mode 20 + 0.1CB 300

t

F

t

SU:STO

C

(Note 12) 400 pF

B

Standard mode 20 + 0.1C

Fast mode 0.6

Standard mode 4.0

300

B

ns

ms

I/O Capacitance (SDA, SCL) C

Oscillator Stop Flag (OSF) Delay

t

OSF

I/O

(Note 13) 10

(Note 14) 100

pF

ms

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POWER-UP/POWER-DOWN CHARACTERISTICS

(TA = -40°C to +85°C) (Note 1, Figure 1)

PARAMETER SYMBOL MIN TYP MAX UNITS

DS1338 I2C RTC with 56-Byte NV RAM

Recovery at Power-Up (Note 15) t

VCC Fall Time; V

VCC Rise Time; V

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 not production tested. All voltages are referenced to ground. SCL only. SDA and SQW/OUT. I

—SCL clocking at max frequency = 400kHz.

CCA

Specified with the I Measured with a 32.768kHz crystal attached to X1 and X2. 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

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 is released.

C

—total capacitance of one bus line in pF.

B

Guaranteed by design. Not production tested.

The parameter t

0.0V ≤ V This delay applies only if the oscillator is enabled and running. If the oscillator is disabled or stopped, no power-up delay occurs.

PF(MAX)

PF(MIN)

≤ V

CC

to V

2

C bus inactive.

HD:DAT

is the time period the oscillator must be stopped for the OSF flag to be set over the voltage range of

OSF

and 1.3V ≤ V

CC MAX

t

PF(MIN)

t

PF(MAX)

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

≤ 3.7V.

BAT

Figure 1. Power-Up/Power-Down Timing

V

PF(max)

V

PF(min)

CC

2 ms

REC

300

VCCF

0

VCCR

of the SCL signal) to bridge

IHMIN

) of the SCL signal.

LOW

≥ to 250ns must then be met. This is

SU:DAT

R MAX

+ t

= 1000 + 250 = 1250ns before the SCL line

SU:DAT

ms

INPUTS

OUTPUTS

t

VCCF

RECOGNIZED

VALID

t

VCCR

t

REC

DON'T CARE

RECOGNIZED

HIGH-Z

VALID

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Figure 2. Timing Diagram

A

8

DS1338 I2C RTC with 56-Byte NV RAM

Figure 3. Block Diagram

"C" VERSION

ONLY

X1

OSCILLATOR AND

X2

DIVIDER

POWER CONTROL

SCL

SDA

SERIAL BUS

INTERFACE AND

DDRESS

REGISTER

1Hz/4.096kHz/8.192kHz/32.768kHz

1Hz

CONTROL

LOGIC

Dallas

Semiconductor

DS133

MUX/

BUFFER

RAM

(56 x 8)

CLOCK,

CALENDAR, ND CONTROL REGISTERS

USER BUFFER

(7 BYTES)

SQW/OUT

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