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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M41T82ZM6F SO-8 Tape And Reel -40 85
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1.081 10000 12
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ECCN (US):

EAR99

Country of Origin:

MOROCCO

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M41T82RM6F SO-8 Tape And Reel -40 85
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1.081 10000 12
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ECCN (US):

EAR99

Country of Origin:

MOROCCO

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DIGIKEY WORLDWIDE 3748 1 Order Now
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3748

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597

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14629

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4379

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Distributor reported inventory date: 2019-11-26

Get sample
M41T82SM6F SO-8 Tape And Reel -40 85
Active
1.081 10000 12
MORE INFO

ECCN (US):

EAR99

Country of Origin:

MOROCCO

Check Availability

Distributor availability ofM41T82SM6F

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Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 2160 1 Order Now
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Distributor reported inventory date: 2019-11-26

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M41T82ZM6F

Package

SO-8

Packing Type

Tape And Reel

Unit Price (US$)

1.081*

Distributor availability ofM41T82ZM6F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 3086 1 Order Now
ARROW EUROPE 2500 0 Order Now
Newark Element14 AMERICA 23 0 Order Now
MOUSER WORLDWIDE 2896 1 Order Now
Farnell Element14 EUROPE 1488 1 Order Now

Distributor reported inventory date: 2019-11-26

Distributor Name

DIGIKEY

Stock

3086

Min.Order

1

Region

WORLDWIDE Order Now

ARROW

Stock

2500

Min.Order

0

Region

EUROPE Order Now

Newark Element14

Stock

23

Min.Order

0

Region

AMERICA Order Now

MOUSER

Stock

2896

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

1488

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2019-11-26

Operating Temperature (°C)

(min)

-40

(max)

85

Marketing Status

Active

Unit Price (US$)

1.081

Quantity

10000

NVRAM size (B)

12

ECCN (US)

EAR99

Country of Origin

MOROCCO

M41T82RM6F

Package

SO-8

Packing Type

Tape And Reel

Unit Price (US$)

1.081*

Distributor availability ofM41T82RM6F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 3748 1 Order Now
FUTURE WORLDWIDE 5000 2500 Order Now
ARROW EUROPE 10000 0 Order Now
Newark Element14 AMERICA 597 0 Order Now
MOUSER WORLDWIDE 14629 1 Order Now
Farnell Element14 EUROPE 4379 1 Order Now
ANGLIA Live EUROPE 2495 1 Order Now

Distributor reported inventory date: 2019-11-26

Distributor Name

DIGIKEY

Stock

3748

Min.Order

1

Region

WORLDWIDE Order Now

FUTURE

Stock

5000

Min.Order

2500

Region

WORLDWIDE Order Now

ARROW

Stock

10000

Min.Order

0

Region

EUROPE Order Now

Newark Element14

Stock

597

Min.Order

0

Region

AMERICA Order Now

MOUSER

Stock

14629

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

4379

Min.Order

1

Region

EUROPE Order Now

ANGLIA Live

Stock

2495

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2019-11-26

Operating Temperature (°C)

(min)

-40

(max)

85

Marketing Status

Active

Unit Price (US$)

1.081

Quantity

10000

NVRAM size (B)

12

ECCN (US)

EAR99

Country of Origin

MOROCCO

M41T82SM6F

Package

SO-8

Packing Type

Tape And Reel

Unit Price (US$)

1.081*

Distributor availability ofM41T82SM6F

Distributor Name
Region Stock Min. Order Third party link
DIGIKEY WORLDWIDE 2160 1 Order Now
RS COMPONENTS EUROPE 2500 1 Order Now
AVNET AMERICA 5000 0 Order Now
FUTURE WORLDWIDE 2500 2500 Order Now
ARROW EUROPE 10000 0 Order Now
Newark Element14 AMERICA 625 0 Order Now
MOUSER WORLDWIDE 11883 1 Order Now
Farnell Element14 EUROPE 1149 1 Order Now

Distributor reported inventory date: 2019-11-26

Distributor Name

DIGIKEY

Stock

2160

Min.Order

1

Region

WORLDWIDE Order Now

RS COMPONENTS

Stock

2500

Min.Order

1

Region

EUROPE Order Now

AVNET

Stock

5000

Min.Order

0

Region

AMERICA Order Now

FUTURE

Stock

2500

Min.Order

2500

Region

WORLDWIDE Order Now

ARROW

Stock

10000

Min.Order

0

Region

EUROPE Order Now

Newark Element14

Stock

625

Min.Order

0

Region

AMERICA Order Now

MOUSER

Stock

11883

Min.Order

1

Region

WORLDWIDE Order Now

Farnell Element14

Stock

1149

Min.Order

1

Region

EUROPE Order Now

Distributor reported inventory date: 2019-11-26

Operating Temperature (°C)

(min)

-40

(max)

85

Marketing Status

Active

Unit Price (US$)

1.081

Quantity

10000

NVRAM size (B)

12

ECCN (US)

EAR99

Country of Origin

MOROCCO

(*) 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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Technical Documentation

    • 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
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      AN1011
      Battery technology used in NVRAM and real-time clock (RTC) products from ST
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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
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      AN1216
      Implementing a periodic alarm with TIMEKEEPER® and serial real-time clocks (RTCs)
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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
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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

Publications and Collaterals

    • Description Version Size Action
      Serial real-time clock ICs 1.0
      827.11 KB
      PDF

      Serial real-time clock ICs

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
M41T82RM6F
Active
SO-8 Industrial Ecopack1
M41T82SM6F
Active
SO-8 Industrial Ecopack1
M41T82ZM6F
Active
SO-8 Industrial Ecopack1

M41T82RM6F

Package:

SO-8

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO-8

Grade

Industrial

RoHS Compliance Grade

Ecopack1

M41T82SM6F

Package:

SO-8

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO-8

Grade

Industrial

RoHS Compliance Grade

Ecopack1

M41T82ZM6F

Package:

SO-8

Material Declaration**:

PDF XML

Marketing Status

Active

Package

SO-8

Grade

Industrial

RoHS Compliance Grade

Ecopack1

(**) 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.

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