Maxim DS3232 Series General Description Manual

Extremely accurate i2c rtc with integrated crystal and sram

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19-5337; Rev 5; 7/10
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
2
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.
Servers
Telematics
Typical Operating Circuit
V
CC
R
= t
/ C
PU
R
B
V
CC
R
R
PU
PU
SCL
SCL
SDA
SDA
RST
RST
PUSH-
μP
N.C.
BUTTON
N.C.
RESET
N.C.
N.C.
N.C.
N.C.
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim's website at www.maxim-ic.com.
Extremely Accurate I
Integrated Crystal and SRAM
CC
Applications
Utility Power Meters
GPS
V
CC
V
CC
INT/SQW
32kHz
V
BAT
DS3232
N.C.
N.C.
N.C.
N.C.
N.C.
GND
______________________________________________ Maxim Integrated Products
♦ 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
♦ Register for Aging Trim
♦ RST Input/Output
♦ 300-Mil, 20-Pin SO Package
♦ Underwriters Laboratories Recognized
Ordering Information
PART
TEMP RANGE
DS3232S#
0°C to +70°C
DS3232SN#
-40°C to +85°C
# 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.
TOP VIEW
N.C.
1
N.C.
2
32kHz
3
V
4
CC
INT/SQW
5
RST
6
N.C.
7
N.C.
8
N.C.
9
N.C.
10
2
C RTC with
Features
PIN-
TOP
PACKAGE
MARK
20 SO
DS3232
20 SO
DS3232N
Pin Configuration
20
SCL
19
N.C.
18
SCL
17
SDA
16
V
DS3232
BAT
15
GND
14
N.C.
13
N.C.
12
N.C.
11
N.C.
SO
1

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Summary of Contents for Maxim Maxim DS3232 Series

  • Page 1 N.C. N.C. N.C. RESET N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. N.C. ______________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
  • Page 2: Absolute Maximum Ratings

    Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four- layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. 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.
  • Page 3 Extremely Accurate I C RTC with Integrated Crystal and SRAM ELECTRICAL CHARACTERISTICS (continued) = 2.3V to 5.5V, V = active supply (see Table 1), T = -40°C to +85°C, unless otherwise noted.) (Typical values are at V 3.3V, V = 3.0V, and T = +25°C, unless otherwise noted.) (Notes 2, 3) PARAMETER SYMBOL...
  • Page 4: Ac Electrical Characteristics

    Extremely Accurate I C RTC with Integrated Crystal and SRAM AC ELECTRICAL CHARACTERISTICS (Active supply (see Table 1) = 2.3V to 5.5V, T = -40°C to +85°C, unless otherwise noted.) (Note 2) PARAMETER SYMBOL CONDITIONS UNITS Fast mode SCL Clock Frequency Standard mode 0.04 Fast mode...
  • Page 5 Extremely Accurate I C RTC with Integrated Crystal and SRAM Pushbutton Reset Timing Power-Switch Timing PF(MAX) PF(MIN) VCCR VCCF _____________________________________________________________________...
  • Page 6: Serial Bus

    Extremely Accurate I C RTC with Integrated Crystal and SRAM Data Transfer on I C Serial Bus HD:STA HIGH SU:STA HD:STA SU:STO HD:DAT SU:DAT STOP START REPEATED START NOTE: TIMING IS REFERENCED TO V AND V IL(MAX) IH(MIN) WARNING: Negative undershoots below -0.3V while the part is in battery-backed mode may cause loss of data.
  • Page 7: Typical Operating Characteristics

    Extremely Accurate I C RTC with Integrated Crystal and SRAM Typical Operating Characteristics = +3.3V, T = +25°C, unless otherwise noted.) STANDBY SUPPLY CURRENT SUPPLY CURRENT vs. SUPPLY VOLTAGE vs. SUPPLY VOLTAGE 1000 SCL = SDA = V = 0V BB32kHz = 0 RST ACTIVE BBSQW = 0...
  • Page 8: Block Diagram

    Extremely Accurate I C RTC with Integrated Crystal and SRAM Block Diagram 32kHz OSCILLATOR AND INT/SQW CAPACITOR ARRAY SQUARE-WAVE BUFFER; CONTROL LOGIC/ INT/SQW CONTROL DIVIDER VOLTAGE REFERENCE; DEBOUNCE CIRCUIT; PUSHBUTTON RESET DS3232 TEMPERATURE CONTROL AND STATUS POWER CONTROL SENSOR REGISTERS SRAM C INTERFACE AND CLOCK AND CALENDAR...
  • Page 9: Pin Description

    The device is UL recognized to ensure against reverse charging when used with a primary lithium battery. Go to www.maxim-ic.com/qa/info/ul. Serial-Data Input/Output. This pin is the data input/output for the I C serial interface. This open-drain pin requires an external pullup resistor.
  • Page 10: Address Map

    Extremely Accurate I C RTC with Integrated Crystal and SRAM Power Control After the internal timer has expired (PB ), the DS3232 continues to monitor the RST line. If the line is still low, the This function is provided by a temperature-compensat- ed voltage reference and a comparator circuit that DS3232 continuously monitors the line looking for a rising edge.
  • Page 11: Clock And Calendar

    Extremely Accurate I C RTC with Integrated Crystal and SRAM Figure 1. Address Map for DS3232 Timekeeping Registers and SRAM BIT 7 BIT 0 ADDRESS BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 FUNCTION RANGE 10 Seconds Seconds Seconds 00–59...
  • Page 12 Extremely Accurate I C RTC with Integrated Crystal and SRAM hours register is defined as the 12- or 24-hour mode Alarms select bit. When high, 12-hour mode is selected. In 12- The DS3232 contains two time-of-day/date alarms. Alarm hour mode, bit 5 is the AM/PM bit with logic-high being 1 can be set by writing to registers 07h to 0Ah.
  • Page 13: Special-Purpose Registers

    Extremely Accurate I C 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 EOSC NAME: BBSQW CONV INTCN A2IE A1IE POR*: * POR is defined as the first application of power to the device, either V or V Special-Purpose Registers the square wave has been enabled.
  • Page 14 Extremely Accurate I C 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: BB32kHz CRATE1 CRATE0 EN32kHz POR*: * POR is defined as the first application of power to the device, either V or V Control/Status Register (0Fh) Bit 3: Enable 32kHz Output (EN32kHz).
  • Page 15 Extremely Accurate I C 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*: Temperature Register (Upper Byte) (11h) BIT 7 BIT 6 BIT 5...
  • Page 16 Extremely Accurate I C RTC with Integrated Crystal and SRAM MSB FIRST SLAVE DATA DATA ACK/ ADDRESS NACK 1–7 1–7 1–7 IDLE START REPEATED IF MORE BYTES CONDITION STOP CONDITION ARE TRANSFERRED REPEATED START Figure 2. I C Data Transfer Overview C Serial Data Bus Data valid: The state of the data line represents valid data when, after a START condition, the data...
  • Page 17 Extremely Accurate I C RTC with Integrated Crystal and SRAM <SLAVE ADDRESS> <R/W> <WORD ADDRESS (n)> <DATA (n)> <DATA (n + 1)> <DATA (n + X) 1101000 XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX S - START SLAVE TO MASTER MASTER TO SLAVE A - ACKNOWLEDGE (ACK) P - STOP DATA TRANSFERRED...
  • Page 18: Package Information

    For the latest package outline information and land patterns, while the serial clock is input on SCL. START and go to www.maxim-ic.com/packages. Note that a “+”, “#”, or STOP conditions are recognized as the beginning “-” in the package code indicates RoHS status only. Package and end of a serial transfer.
  • Page 19: Revision History

    Package Information table Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

This manual is also suitable for:

Maxim ds3232sMaxim ds3232sn

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