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AVAILABLE

EVALUATION KIT AVAILABLE

Functional Diagrams

Pin Configurations appear at end of data sheet.

Functional Diagrams continued at end of data sheet.

UCSP is a trademark of Maxim Integrated Products, Inc.

For pricing, delivery, and

ordering information, please contact Maxim Direct

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

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

C bidirectional bus.

A precision temperature-compensated voltage refer-

ence and comparator circuit monitors the status of V

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 µP reset.

Applications

Servers Utility Power Meters

Telematics GPS

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

C Interface

♦ 3.3V Operation

♦ Digital Temp Sensor Output: ±3°C Accuracy

♦ Register for Aging Trim

♦ RST Input/Output

♦ 300-Mil, 20-Pin SO Package

♦ Underwriters Laboratories Recognized

Extremely Accurate I

C RTC with

Integrated Crystal and SRAM

19-5337; Rev 5; 7/10

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

DS3232

SCL

= t

/ C

INT/SQW

32kHz

BAT

PUSH-

BUTTON

RESET

SDA

RST

N.C.

GND

μP

N.C.

SCL

RST

SDA

Typical Operating Circuit

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.

Pin Configuration

DS3232

TOP VIEW

SCL

N.C.

SCL

SDAV

32kHz

N.C.

BAT

GND

N.C.

N.C.N.C.

N.C.

RST

INT/SQW

N.C.

N.C.N.C.

N.C.

DS3232

Summary of content (19 pages)

PAGE 1
EVALUATION KIT AVAILABLE DS3232 LE AVAILAB Extremely Accurate I2C RTC with Integrated Crystal and SRAM General Description Features The DS3232 is a low-cost temperature-compensated crystal oscillator (TCXO) with a very accurate, temperature-compensated, integrated real-time clock (RTC) and 236 bytes of battery-backed SRAM. Additionally, the DS3232 incorporates a battery input and maintains accurate timekeeping when main power to the device is interrupted.
PAGE 2
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM ABSOLUTE MAXIMUM RATINGS Voltage Range on VCC, VBAT, 32kHz, SCL, SDA, RST, INT/SQW Relative to Ground.............................-0.3V to +6.0V Junction-to-Ambient Thermal Resistance (θJC) (Note 1)..55.1°C/W Junction-to-Case Thermal Resistance (θJC) (Note 1)..........24°C/W Operating Temperature Range (noncondensing) .............................................-40°C to +85°C Junction Temperature ...........................................
PAGE 3
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM ELECTRICAL CHARACTERISTICS (continued) (VCC = 2.3V to 5.5V, VCC = active supply (see Table 1), TA = -40°C to +85°C, unless otherwise noted.) (Typical values are at VCC = 3.3V, VBAT = 3.0V, and TA = +25°C, unless otherwise noted.) (Notes 2, 3) MAX UNITS Logic 0 Output, INT/SQW, SDA PARAMETER SYMBOL VOL IOL = 3mA 0.4 V Logic 0 Output, RST, 32kHz VOL IOL = 1mA 0.
PAGE 4
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM AC ELECTRICAL CHARACTERISTICS (Active supply (see Table 1) = 2.3V to 5.5V, TA = -40°C to +85°C, unless otherwise noted.
PAGE 5
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM Pushbutton Reset Timing RST PBDB tRST Power-Switch Timing VCC VPF(MAX) VPF VPF(MIN) tVCCF VPF tVCCR tREC RST Maxim Integrated 5
PAGE 6
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM Data Transfer on I2C Serial Bus SDA tBUF tF tHD:STA tLOW tSP SCL tHIGH tHD:STA tHD:DAT STOP tSU:STA tR START tSU:STO tSU:DAT REPEATED START NOTE: TIMING IS REFERENCED TO VIL(MAX) AND VIH(MIN). WARNING: Negative undershoots below -0.3V while the part is in battery-backed mode may cause loss of data. Limits at -40°C are guaranteed by design and not production tested. All voltages are referenced to ground.
PAGE 7
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM Typical Operating Characteristics (VCC = +3.3V, TA = +25°C, unless otherwise noted.) STANDBY SUPPLY CURRENT vs. SUPPLY VOLTAGE SUPPLY CURRENT vs. SUPPLY VOLTAGE RST ACTIVE SUPPLY CURRENT (nA) 50 900 850 800 750 0 700 2.3 2.8 3.3 3.8 4.3 4.8 5.3 2.3 2.8 3.3 3.8 4.3 4.8 VCC (V) VBAT (V) SUPPLY CURRENT vs. TEMPERATURE FREQUENCY DEVIATION vs. TEMPERATURE vs. AGING 75 DS3232 toc03 0.
PAGE 8
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM Block Diagram 32kHz X1 OSCILLATOR AND CAPACITOR ARRAY INT/SQW CONTROL LOGIC/ DIVIDER X2 SQUARE-WAVE BUFFER; INT/SQW CONTROL N VCC VOLTAGE REFERENCE; DEBOUNCE CIRCUIT; PUSHBUTTON RESET DS3232 RST N VCC VBAT POWER CONTROL TEMPERATURE SENSOR CONTROL AND STATUS REGISTERS GND SRAM SCL I2C INTERFACE AND ADDRESS REGISTER DECODE SDA USER BUFFER (7 BYTES) Detailed Description The DS3232 is a serial RTC driven by a temperaturecompens
PAGE 9
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM Pin Description PIN NAME 1, 2, 7–14, 19 FUNCTION N.C. 3 32kHz 32kHz Push-Pull Output. If disabled with either EN32kHz = 0 or BB32kHz = 0, the state of the 32kHz pin will be low. 4 VCC DC Power Pin for Primary Power Supply. This pin should be decoupled using a 0.1μF to 1.0μF capacitor. No Connection. Not connected internally. Must be connected to ground. 5 Active-Low Interrupt or Square-Wave Output.
PAGE 10
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM Power Control This function is provided by a temperature-compensated voltage reference and a comparator circuit that monitors the VCC level. When VCC is greater than VPF, the part is powered by VCC. When VCC is less than VPF but greater than VBAT, the DS3232 is powered by VCC. If V CC is less than V PF and is less than V BAT , the device is powered by VBAT. See Table 1. Table 1.
PAGE 11
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM Figure 1.
PAGE 12
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM Alarms hours register is defined as the 12- or 24-hour mode select bit. When high, 12-hour mode is selected. In 12hour mode, bit 5 is the AM/PM bit with logic-high being PM. In 24-hour mode, bit 5 is the 20-hour bit (20–23 hours). The century bit (bit 7 of the month register) is toggled when the years register overflows from 99 to 00. The day-of-week register increments at midnight.
PAGE 13
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM Control Register (0Eh) BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 NAME: EOSC BBSQW CONV RS2 RS1 INTCN A2IE A1IE POR*: 0 0 0 1 1 1 0 0 *POR is defined as the first application of power to the device, either VBAT or VCC. Special-Purpose Registers The DS3232 has two additional registers (control and control/status) that control the real-time clock, alarms, and square-wave output.
PAGE 14
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM Control/Status Register (0Fh) BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 NAME: OSF BB32kHz CRATE1 CRATE0 EN32kHz BSY A2F A1F POR*: 1 1 0 0 1 0 0 0 *POR is defined as the first application of power to the device, either VBAT or VCC. Control/Status Register (0Fh) Bit 7: Oscillator Stop Flag (OSF).
PAGE 15
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM Aging Offset (10h) BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 NAME: SIGN DATA DATA DATA DATA DATA DATA DATA POR*: 0 0 0 0 0 0 0 0 Temperature Register (Upper Byte) (11h) BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 NAME: SIGN DATA DATA DATA DATA DATA DATA DATA POR*: 0 0 0 0 0 0 0 0 Temperature Register (Lower Byte) (12h) BIT 7 BIT 6 BIT 5 NAME: BIT 4 BIT 3 DATA DATA POR*: 0
PAGE 16
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM MSB FIRST MSB LSB MSB LSB SDA SLAVE ADDRESS SCL 1–7 IDLE START CONDITION R/W 8 ACK 9 DATA 1–7 ACK 8 9 REPEATED IF MORE BYTES ARE TRANSFERRED DATA 1–7 ACK/ NACK 8 9 STOP CONDITION REPEATED START Figure 2. I2C Data Transfer Overview I2C Serial Data Bus The DS3232 supports a bidirectional I2C bus and data transmission protocol.
PAGE 17
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM S 1101000 0 A XXXXXXXX A XXXXXXXX S - START SLAVE TO MASTER A - ACKNOWLEDGE (ACK) P - STOP R/W - READ/WRITE OR DIRECTION BIT ADDRESS A XXXXXXXX
PAGE 18
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM The DS3232 can operate in the following two modes: Slave receiver mode (DS3232 write mode): Serial data and clock are received through SDA and SCL. After each byte is received, an acknowledge bit is transmitted. START and STOP conditions are recognized as the beginning and end of a serial transfer. Address recognition is performed by hardware after reception of the slave address and direction bit.
PAGE 19
DS3232 Extremely Accurate I2C RTC with Integrated Crystal and SRAM Revision History REVISION NUMBER REVISION DATE 0 9/05 1 11/05 2 3 4 3/06 10/07 10/08 DESCRIPTION Initial release — Changed RoHS note wording for the Ordering Information table 1 Corrected the Ordering Information part numbers 1 Changed the reference of Figure 4 to Table 1 in the AC Electrical Characteristics table 4 Corrected the supply current units from μA to nA and added BSY = 0 to the Supply Current vs.