Serial I²C bus real-time clock (RTC) with battery switchover

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  • The M41T8x are low-power serial I2C real-time clocks (RTCs) with a built-in 32.768 kHz oscillator (external crystal-controlled for the QFN16 and SO8 packages, embedded crystal for the SOX18 package). Eight bytes of the register map (see Table 2 on page 23) are used for the clock/calendar function and are configured in binary-coded decimal (BCD) format. An additional 17 bytes of the register map provide status/control of the two alarms, watchdog, 8-bit counter, and square wave functions. An additional seven bytes are made available as user SRAM.

    Addresses and data are transferred serially via a two-line, bidirectional I2C interface. The built-in address register is incremented automatically after each WRITE or READ data byte. The M41T8x has a built-in power sense circuit which detects power failures and automatically switches to the battery supply when a power failure occurs. The energy needed to sustain the clock operations can be supplied by a small lithium button battery when a power failure occurs.
    Functions available to the user include a non-volatile, time-of-day clock/calendar, two alarm interrupts, watchdog timer, programmable 8-bit counter, and square wave outputs. The eight clock address locations contain the century, year, month, date, day, hour, minute, second, and tenths/hundredths of a second in 24-hour BCD format. Corrections for 28, 29 (leap year), 30, and 31 day months are made automatically. The M41T83 is supplied in either a QFN16 or an SOX18, 300 mil SOIC which includes an embedded 32 KHz crystal. The SOX18 package requires only a user-supplied battery to provide non-volatile operation. The M41T82 is available only in an SO8 package.

    Key Features

    • Ultra-low battery supply current of 365 nA
    • Factory-calibrated accuracy of ±5 ppm typical after 2 reflows (SOX18)
      • Much better accuracies achievable using built-in programmable analog and digital calibration circuits
    • 2.0 V to 5.5 V clock operating voltage
    • Counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century
    • Automatic switchover and reset output circuitry (fixed reference)
      • M41T83S: VCC= 3.00 V to 5.50 V
      • M41T83R: VCC= 2.70 V to 5.50 V
      • M41T83Z: VCC= 2.38 V to 5.50 V
    • Serial interface supports I2C bus (400 kHz protocol)
    • Programmable alarm with interrupt function (valid even during battery backup mode)
    • Optional 2ndprogrammable alarm available
    • Square wave output defaults to 32 KHz on power-up (M41T83 only)
    • RESET (RST) output
    • Watchdog timer
    • Programmable 8-bit counter/timer
    • 7 bytes of battery-backed user SRAM
    • Battery low flag
    • Low operating current of 80 μA
    • Oscillator stop detection
    • Battery or SuperCap™ backup
    • Operating temperature of –40 °C to 85 °C
    • Package options
      • a 16-lead QFN (M41T83)
      • an 8-lead SOIC (M41T82) or
      • an 18-lead embedded crystal SOIC (M41T83)
    • RoHS compliance: lead-free components are compliant with the RoHS directive

Circuit Diagram

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M41T83SMY6F SO18 with embedded crystal Tape And Reel -40 85
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M41T83SMY6F

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Operating Temperature (°C)

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(max)

85

Marketing Status

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Unit Price (US$)

1.965

Quantity

10000

NVRAM size (B)

12

ECCN (US)

EAR99

Country of Origin

MALAYSIA

M41T83ZMY6F

Package

SO18 with embedded crystal

Packing Type

Tape And Reel

Unit Price (US$)

1.965*

Distributor availability ofM41T83ZMY6F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 2764 1 Order Now
Newark Element14 AMERICA 140 0 Order Now
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Distributor reported inventory date: 2019-07-14

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Newark Element14

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140

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1076

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1204

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Region

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Distributor reported inventory date: 2019-07-14

Operating Temperature (°C)

(min)

-40

(max)

85

Marketing Status

Active

Unit Price (US$)

1.965

Quantity

10000

NVRAM size (B)

12

ECCN (US)

EAR99

Country of Origin

MALAYSIA

M41T83RQA6F

Package

VFQFPN 16 4x4x1.0

Packing Type

Tape And Reel

Unit Price (US$)

1.318*

Distributor availability ofM41T83RQA6F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 1156 1 Order Now
FUTURE WORLDWIDE 1000 1000 Order Now
ARROW EUROPE 17000 0 Order Now
Newark Element14 AMERICA 250 0 Order Now
MOUSER WORLDWIDE 397 1 Order Now
Farnell Element14 EUROPE 647 1 Order Now

Distributor reported inventory date: 2019-07-14

Distributor Name

DIGIKEY

Stock

1156

Min.Order

1

Region

WORLDWIDE Order Now

FUTURE

Stock

1000

Min.Order

1000

Region

WORLDWIDE Order Now

ARROW

Stock

17000

Min.Order

0

Region

EUROPE Order Now

Newark Element14

Stock

250

Min.Order

0

Region

AMERICA Order Now

MOUSER

Stock

397

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

647

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2019-07-14

Operating Temperature (°C)

(min)

-40

(max)

85

Marketing Status

Active

Unit Price (US$)

1.318

Quantity

10000

NVRAM size (B)

12

ECCN (US)

EAR99

Country of Origin

MALAYSIA

M41T83ZQA6F

Package

VFQFPN 16 4x4x1.0

Packing Type

Tape And Reel

Unit Price (US$)

1.318*

Distributor availability ofM41T83ZQA6F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 859 1 Order Now
ARROW EUROPE 1000 0 Order Now
MOUSER WORLDWIDE 907 1 Order Now

Distributor reported inventory date: 2019-07-14

Distributor Name

DIGIKEY

Stock

859

Min.Order

1

Region

WORLDWIDE Order Now

ARROW

Stock

1000

Min.Order

0

Region

EUROPE Order Now

MOUSER

Stock

907

Min.Order

1

Region

WORLDWIDE Order Now

Distributor reported inventory date: 2019-07-14

Operating Temperature (°C)

(min)

-40

(max)

85

Marketing Status

Active

Unit Price (US$)

1.318

Quantity

10000

NVRAM size (B)

12

ECCN (US)

EAR99

Country of Origin

MALAYSIA

M41T83SQA6F

Package

VFQFPN 16 4x4x1.0

Packing Type

Tape And Reel

Unit Price (US$)

1.318*

Distributor availability ofM41T83SQA6F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 2483 1 Order Now
RS COMPONENTS EUROPE 705 1 Order Now
ARROW EUROPE 1000 0 Order Now
ARROW AMERICA 3000 1000 Order Now
MOUSER WORLDWIDE 1539 1 Order Now

Distributor reported inventory date: 2019-07-14

Distributor Name

DIGIKEY

Stock

2483

Min.Order

1

Region

WORLDWIDE Order Now

RS COMPONENTS

Stock

705

Min.Order

1

Region

EUROPE Order Now

ARROW

Stock

1000

Min.Order

0

Region

EUROPE Order Now

ARROW

Stock

3000

Min.Order

1000

Region

AMERICA Order Now

MOUSER

Stock

1539

Min.Order

1

Region

WORLDWIDE Order Now

Distributor reported inventory date: 2019-07-14

Operating Temperature (°C)

(min)

-40

(max)

85

Marketing Status

Active

Unit Price (US$)

1.318

Quantity

10000

NVRAM size (B)

12

ECCN (US)

EAR99

Country of Origin

MALAYSIA

M41T83RMY6F

Package

SO18 with embedded crystal

Packing Type

Tape And Reel

Unit Price (US$)

1.965*

Distributor availability ofM41T83RMY6F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 6055 1 Order Now
AVNET AMERICA 2000 0 Order Now
FUTURE WORLDWIDE 1000 1000 Order Now
Newark Element14 AMERICA 194 0 Order Now
MOUSER WORLDWIDE 1364 1 Order Now
Farnell Element14 EUROPE 1800 1 Order Now

Distributor reported inventory date: 2019-07-14

Distributor Name

DIGIKEY

Stock

6055

Min.Order

1

Region

WORLDWIDE Order Now

AVNET

Stock

2000

Min.Order

0

Region

AMERICA Order Now

FUTURE

Stock

1000

Min.Order

1000

Region

WORLDWIDE Order Now

Newark Element14

Stock

194

Min.Order

0

Region

AMERICA Order Now

MOUSER

Stock

1364

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

1800

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2019-07-14

Operating Temperature (°C)

(min)

-40

(max)

85

Marketing Status

Active

Unit Price (US$)

1.965

Quantity

10000

NVRAM size (B)

12

ECCN (US)

EAR99

Country of Origin

MALAYSIA

(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office  or our Distributors

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    • Description Version Size Action
      DS4858
      Serial I2C bus real-time clock (RTC) with battery switchover
      18.0
      2.18 MB
      PDF
      DS4858

      Serial I2C bus real-time clock (RTC) with battery switchover

    • Description Version Size Action
      AN3060
      Applications guide for serial real-time clocks (RTCs)
      3.0
      878.56 KB
      PDF
      AN1011
      Battery technology used in NVRAM and real-time clock (RTC) products from ST
      4.0
      248.17 KB
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      AN2678
      Extremely accurate timekeeping over temperature using adaptive calibration
      2.1
      214.39 KB
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      AN934
      How to use the digital calibration feature in TIMEKEEPER® and serial real-time clock (RTC) products
      4.1
      123.42 KB
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      AN1216
      Implementing a periodic alarm with TIMEKEEPER® and serial real-time clocks (RTCs)
      2.0
      192.89 KB
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      AN4641
      Integrating TIMEKEEPER® and real-time clock supervisor functions
      1.0
      479.28 KB
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      AN923
      Managing century information using serial real-time clocks and TIMEKEEPER® NVRAMs
      4.0
      142.23 KB
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      AN1572
      Power-down time-stamp function in serial real-time clocks (RTCs)
      2.0
      171.31 KB
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      AN1336
      Power-fail comparator for NVRAM supervisory devices
      2.0
      127.81 KB
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      AN1012
      Predicting the battery life and data retention period of NVRAMs and serial RTCs
      4.1
      439.45 KB
      PDF
      AN2971
      Using the typical temperature characteristics of 32 KHz crystal to compensate the M41T83 and M41T93 serial real-time clocks
      1.2
      401.74 KB
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      AN3060

      Applications guide for serial real-time clocks (RTCs)

      AN1011

      Battery technology used in NVRAM and real-time clock (RTC) products from ST

      AN2678

      Extremely accurate timekeeping over temperature using adaptive calibration

      AN934

      How to use the digital calibration feature in TIMEKEEPER® and serial real-time clock (RTC) products

      AN1216

      Implementing a periodic alarm with TIMEKEEPER® and serial real-time clocks (RTCs)

      AN4641

      Integrating TIMEKEEPER® and real-time clock supervisor functions

      AN923

      Managing century information using serial real-time clocks and TIMEKEEPER® NVRAMs

      AN1572

      Power-down time-stamp function in serial real-time clocks (RTCs)

      AN1336

      Power-fail comparator for NVRAM supervisory devices

      AN1012

      Predicting the battery life and data retention period of NVRAMs and serial RTCs

      AN2971

      Using the typical temperature characteristics of 32 KHz crystal to compensate the M41T83 and M41T93 serial real-time clocks

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Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
M41T83RMY6F
Active
SO18 with embedded crystal Industrial Ecopack1
M41T83RQA6F
Active
VFQFPN 16 4x4x1.0 Industrial Ecopack2
M41T83SMY6F
Active
SO18 with embedded crystal Industrial Ecopack1
M41T83SQA6F
Active
VFQFPN 16 4x4x1.0 Industrial Ecopack2
M41T83ZMY6F
Active
SO18 with embedded crystal Industrial Ecopack1
M41T83ZQA6F
Active
VFQFPN 16 4x4x1.0 Industrial Ecopack2

M41T83RMY6F

Package:

SO18 with embedded crystal

Material Declaration**:

Marketing Status

Active

Package

SO18 with embedded crystal

Grade

Industrial

RoHS Compliance Grade

Ecopack1

M41T83RQA6F

Package:

VFQFPN 16 4x4x1.0

Material Declaration**:

PDF XML

Marketing Status

Active

Package

VFQFPN 16 4x4x1.0

Grade

Industrial

RoHS Compliance Grade

Ecopack2

M41T83SMY6F

Package:

SO18 with embedded crystal

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO18 with embedded crystal

Grade

Industrial

RoHS Compliance Grade

Ecopack1

M41T83SQA6F

Package:

VFQFPN 16 4x4x1.0

Material Declaration**:

PDF XML

Marketing Status

Active

Package

VFQFPN 16 4x4x1.0

Grade

Industrial

RoHS Compliance Grade

Ecopack2

M41T83ZMY6F

Package:

SO18 with embedded crystal

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO18 with embedded crystal

Grade

Industrial

RoHS Compliance Grade

Ecopack1

M41T83ZQA6F

Package:

VFQFPN 16 4x4x1.0

Material Declaration**:

PDF XML

Marketing Status

Active

Package

VFQFPN 16 4x4x1.0

Grade

Industrial

RoHS Compliance Grade

Ecopack2

(**) The Material Declaration forms available on st.com may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.