DS3232.pdf

Rev 2; 3/06

Extremely Accurate I 2 C RTC with

Integrated Crystal and SRAM

General Description

The DS3232 is a low-cost temperature-compensated

crystal oscillator (TCXO) with a very accurate, tempera-

ture-compensated, integrated real-time clock (RTC) and

236 bytes of battery-backed SRAM. Additionally, the

DS3232 incorporates a battery input and maintains accu-

rate timekeeping when main power to the device is inter-

rupted. The integration of the crystal resonator enhances

the long-term accuracy of the device as well as reduces

the piece-part count in a manufacturing line. The DS3232

is available in commercial and industrial temperature

ranges, and is offered in an industry-standard 20-pin,

300-mil SO package.

The RTC maintains 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 an AM/PM indicator. Two programmable time-of-

day alarms and a programmable square-wave output

are provided. Address and data are transferred serially

through an I 2 C* bidirectional bus.

A precision temperature-compensated voltage refer-

ence and comparator circuit monitors the status of V CC

to detect power failures, to provide a reset output, and

to automatically switch to the backup supply when nec-

essary. Additionally, the RST pin is monitored as a

pushbutton input for generating a reset externally.

Applications

Features

♦

Accuracy ±2ppm from 0°C to +40°C

♦

Accuracy ±3.5ppm from -40°C to +85°C

♦

Battery Backup Input for Continuous

Timekeeping

♦

Operating Temperature Ranges

Commercial: 0°C to +70°C

Industrial: -40°C to +85°C

♦

236 Bytes of Battery-Backed SRAM

♦

Low-Power Consumption

♦

Real-Time Clock Counts Seconds, Minutes,

Hours, Day, Date, Month, and Year with Leap Year

Compensation Valid Up to 2099

♦

Two Time-of-Day Alarms

♦

Programmable Square-Wave Output

♦

Fast (400kHz) I 2 C Interface

♦

3.3V Operation

♦

Digital Temp Sensor Output: ±3°C Accuracy

♦

RST Input/Output

♦

300-Mil, 20-Pin SO Package

♦

Underwriters Laboratory (UL) Recognized

Ordering Information

PART

TEMP RANGE

PIN-

PACKAGE

TOP

MARK

DS3232S#

0°C to +70°C

20 SO

DS3232

DS3232SN#

-40°C to +85°C

20 SO

DS3232N

# Denotes a RoHS-compliant device that may include lead that

is exempt under the RoHS requirements. Lead finish is JESD97

Category e3, and is compatible with both lead-based and

lead-free soldering processes. A "#" anywhere on the top mark

denotes a RoHS-compliant device.

Servers

Utility Power Meters

Telematics

GPS

Typical Operating Circuit

Pin Configuration

V CC

TOP VIEW

R PU = t R / C B

N.C.

SCL

N.C.

SCL

SDA

V CC

N.C.

R PU

V CC

32kHz

SCL

INT/SQW

32kHz

V BAT

V CC

SDA

RST

N.C.

CPU

INT/SQW

DS3232

V BAT

GND

PUSH-

BUTTON

RESET

RST

N.C.

DS3232

N.C.

GND

N.C.

* Purchase of I 2 C components from Maxim Integrated Products, Inc., or one of its sublicensed Associated Companies, conveys a

license under the Philips I 2 C Patent Rights to use these components in an I 2 C system, provided that the system conforms to the I 2 C

Standard Specification as defined by Philips.

______________________________________________ Maxim Integrated Products 1

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Extremely Accurate I 2 C RTC with

Integrated Crystal and SRAM

ABSOLUTE MAXIMUM RATINGS

Voltage Range on V CC , V BAT , 32kHz, SCL, SDA, RST,

INT/SQW Relative to Ground.............................-0.3V to +6.0V

Operating Temperature Range

(noncondensing) .............................................-40°C to +85°C

Junction Temperature ......................................................+125°C

Storage Temperature Range ...............................-40°C to +85°C

Lead Temperature

(soldering, 10s) .....................................................+260°C/10s

Soldering Temperature (reflow, 2 times max) .......See IPC/JEDEC

J-STD-020 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

absolute maximum rating conditions for extended periods may affect device reliability.

RECOMMENDED DC OPERATING CONDITIONS

(T A = -40°C to +85°C, unless otherwise noted.) (Notes 1, 2)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Supply Voltage

V CC

2.3

3.3

5.5

V BAT

2.3

3.0

5.5

Logic 1 Input SDA, SCL

V IH

0.7 x

V CC

V CC +

0.3

Logic 0 Input SDA, SCL

V IL

-0.3

+0.3 x

V CC

Pullup Voltage

(SDA, SCL, INT/SQW)

V PU

V CC = 0V

5.5V

ELECTRICAL CHARACTERISTICS

(V CC = 2.3V to 5.5V, V CC = active supply (see Table 1), T A = -40°C to +85°C, unless otherwise noted.) (Typical values are at V CC =

3.3V, V BAT = 3.0V , and T A = +25°C, unless otherwise noted.) (Notes 1, 2)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Active Supply Current

I CCA

32kHz output off

(Notes 3, 4)

V CC = 3.3V

200

µA

V CC = 5.5V

325

I 2 C bus inactive, 32kHz

output off, SQW output off

(Note 4)

V CC = 3.3V

120

Standby Supply Current

I CCS

µA

V CC = 5.5V

160

Temperature Conversion Current I CCSCONV

I 2 C bus inactive, 32kHz

output off, SQW output off V CC = 5.5V

V CC = 3.3V

500

µA

600

Power-Fail Voltage

V PF

2.45

2.575

2.70

ACTIVE SUPPLY (Table 1 ) (2.3V to 5.5V, T A = -40°C to +85°C, unless otherwise noted) (Note 1)

Logic 1 Output, 32kHz

I OH = -1mA

I OH = -0.75mA

I OH = -0.14mA

V OH

Active supply > 3.3V,

3.3V > active supply > 2.7V,

2.7V > active supply > 2.3V

2.0

2 _____________________________________________________________________

Extremely Accurate I 2 C RTC with

Integrated Crystal and SRAM

ELECTRICAL CHARACTERISTICS (continued)

(V CC = 2.3V to 5.5V, V CC = active supply (see Table 1), T A = -40°C to +85°C, unless otherwise noted.) (Typical values are at V CC =

3.3V, V BAT = 3.0V , and T A = +25°C, unless otherwise noted.) (Notes 1, 2)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Logic 0 Output, INT/SQW, SDA

V OL

I OL = 3mA

0.4

Logic 0 Output, RST, 32kHz

V OL

I OL = 1mA

0.4

Output Leakage Current 32kHz,

INT/SQW, SDA

I LO

Output high impedance

-1

µA

Input Leakage SCL

I LI

-1

µA

RST Pin I/O Leakage

I OL

RST high impedance (Note 5)

-200

+10

µA

TCXO

Output Frequency

f OUT V CC = 3.3V or V BAT = 3.3V

32.768

kHz

0°C to +40°C

-2

Frequency Stability vs.

Temperature

V CC = 3.3V or

V BAT = 3.3V

∆ f/f OUT

-40°C to 0°C and

+40°C to +85°C

-3.5

+3.5

ppm

Frequency Stability vs. Voltage

∆ f/V

V CC = 3.3V or V BAT = 3.3V

ppm/V

-40°C

0.7

Trim Register Frequency

Sensitivity per LSB

∆ f/LSB Specified at:

+25°C

0.1

ppm

+70°C

0.4

+85°C

0.8

Temperature Accuracy

Temp

V CC = 3.3V or V BAT = 3.3V

-3

°C

Crystal Aging

∆ f/f 0

After reflow,

not production tested

First year

±1.0

ppm

0–10 years

±5.0

ELECTRICAL CHARACTERISTICS

( V CC = 0V, V BAT = 2.3V to 5.5V , T A = -40°C to +85°C, unless otherwise noted.) (Note 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Active Battery Current

(Note 4)

I BATA

EOSC = 0, BBSQW = 0,

SCL = 400kHz, BB32kHz = 0 V BAT = 5.5V

V BAT = 3.3V

µA

200

Timekeeping Battery Current

(Note 4)

EOSC = 0, BBSQW = 0,

SCL = SDA = 0V,

BB32kHz = 0

V BAT = 3.4V

1.5

2.5

I BAT

µA

V BAT = 5.5V

1.5

3.0

Temperature Conversion Current

I TC

EOSC = 0, BBSQW = 0, SCL = SDA = 0V

600

µA

Data-Retention Current

I BATTC

EOSC = 1, SCL = SDA = 0V, +25°C

100

_____________________________________________________________________ 3

Extremely Accurate I 2 C RTC with

Integrated Crystal and SRAM

AC ELECTRICAL CHARACTERISTICS

(Active supply (see Table 1) = 2.3V to 5.5V, T A = -40°C to +85°C, unless otherwise noted.) (Note 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

SCL Clock Frequency

f SCL

Fast mode

100

400

kHz

Standard mode

0.04

100

Bus Free Time Between STOP

and START Conditions

t BUF

Fast mode

1.3

µs

Standard mode

4.7

Hold Time (Repeated) START

Condition (Note 6)

t HD:STA

Fast mode

0.6

µs

Standard mode

4.0

Low Period of SCL Clock

t LOW

Fast mode

1.3

25,000

µs

Standard mode

4.7

25,000

High Period of SCL Clock

t HIGH

Fast mode

0.6

µs

Standard mode

4.0

Data Hold Time (Notes 7, 8)

t HD:DAT

Fast mode

0.9

µs

Standard mode

0.9

Data Setup Time (Note 9)

t SU:DAT

Fast mode

100

Standard mode

250

Start Setup Time

t SU:STA

Fast mode

0.6

µs

Standard mode

4.7

Rise Time of Both SDA and SCL

Signals (Note 10)

t R

Fast mode

20 +

0.1C B

300

Standard mode

1000

Fall Time of Both SDA and SCL

Signals (Note 10)

t F

Fast mode

20 +

0.1C B

300

Standard mode

300

Setup Time for STOP Condition

t SU:STO

Fast mode

0.6

µs

Standard mode

4.7

Capacitive Load for Each Bus

Line (Note 10)

C B

400

Capacitance for SDA, SCL

C I/O

Pulse Width of Spikes That Must

Be Suppressed by the Input Filter

t SP

Pushbutton Debounce

PB DB

250

Interface Timeout

t IF

(Note 11)

Reset Active Time

t RST

250

Oscillator Stop Flag (OSF) Delay

t OSF

(Note 12)

100

Temperature Conversion Time

t CONV

125

200

POWER-SWITCH CHARACTERISTICS

(T A = -40°C to +85°C)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

V CC Fall Time; V PF(MAX) to

V PF(MIN)

t VCCF

300

µs

V CC Rise Time; V PF(MIN) to

V PF(MAX)

t VCCR

µs

Recovery at Power-Up

t REC

(Note 13)

125

300

4 _____________________________________________________________________

Extremely Accurate I 2 C RTC with

Integrated Crystal and SRAM

Pushbutton Reset Timing

RST

PB DB

t RST

Power-Switch Timing

V CC

V PF(MAX)

V PF

V PF(MIN)

t VCCF

t VCCR

t REC

RST

_____________________________________________________________________ 5

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