Product overview
Description
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.
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All 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
All tools & software
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Part number Status Description Type Supplier Worldwide,Asia,Europe,Africa,North America,South America,Oceania,Afghanistan,Bahrain,Bangladesh,Bhutan,Brunei,Burma (Myanmar),Cambodia,China,East Timor,India,Indonesia,Iraq,Japan,Jordan,Kazakhstan,Kuwait,Kyrgyzstan,Laos,Malaysia,Maldives,Mongolia,Nepal,Oman,Pakistan,Philippines,Qatar,Russian Federation,Saudi Arabia,Singapore,South Korea,Sri Lanka,Taiwan,Tajikistan,Thailand,Turkmenistan,United Arab Emirates,Uzbekistan,Vietnam,Yemen,Albania,Andorra,Armenia,Austria,Azerbaijan,Belarus,Belgium,Bosnia and Herzegovina,Bulgaria,Croatia,Cyprus,Czech Republic,Denmark,Estonia,Finland,France,Georgia,Germany,Greece,Hungary,Iceland,Ireland,Israel,Italy,Latvia,Liechtenstein,Lithuania,Luxembourg,Macedonia,Malta,Moldova,Monaco,Montenegro,Netherlands,Norway,Poland,Portugal,Romania,San Marino,Serbia,Slovakia,Slovenia,Spain,Sweden,Switzerland,Turkey,Ukraine,United Kingdom,Vatican City,Algeria,Angola,Benin,Botswana,Burkina,Burundi,Cameroon,Cape Verde,Central African Republic,Chad,Comoros,Democratic Republic of Congo,Djibouti,Egypt,Equatorial Guinea,Eritrea,Ethiopia,Gabon,Gambia,Ghana,Guinea,Guinea-Bissau,Ivory Coast,Kenya,Lesotho,Liberia,Libya,Madagascar,Malawi,Mali,Mauritania,Mauritius,Morocco,Mozambique,Namibia,Niger,Nigeria,Rwanda,Sao Tome and Principe,Senegal,Seychelles,Sierra Leone,Somalia,South Africa,Swaziland,Tanzania,Togo,Tunisia,Uganda,Zambia,Zimbabwe,Antigua and Barbuda,Bahamas,Barbados,Belize,Canada,Costa Rica,Dominica,Dominican Republic,El Salvador,Grenada,Guatemala,Haiti,Honduras,Jamaica,Mexico,Nicaragua,Panama,Saint Kitts and Nevis,Saint Lucia,Saint Vincent and the Grenadines,Trinidad and Tobago,United States,Argentina,Bolivia,Brazil,Chile,Colombia,Ecuador,Guyana,Paraguay,Peru,Suriname,Uruguay,Venezuela,Australia,Fiji,Kiribati,Marshall Islands,Micronesia,Nauru,New Zealand,Palau,Papua New Guinea,Samoa,Solomon Islands,Tonga,Tuvalu,Vanuatu STSW-SRTC001
ActiveI2C code for Serial RTC
Clocks and timers software ST Worldwide,Asia,Europe,Africa,North America,South America,Oceania,Afghanistan,Bahrain,Bangladesh,Bhutan,Brunei,Burma (Myanmar),Cambodia,China,East Timor,India,Indonesia,Iraq,Japan,Jordan,Kazakhstan,Kuwait,Kyrgyzstan,Laos,Malaysia,Maldives,Mongolia,Nepal,Oman,Pakistan,Philippines,Qatar,Russian Federation,Saudi Arabia,Singapore,South Korea,Sri Lanka,Taiwan,Tajikistan,Thailand,Turkmenistan,United Arab Emirates,Uzbekistan,Vietnam,Yemen,Albania,Andorra,Armenia,Austria,Azerbaijan,Belarus,Belgium,Bosnia and Herzegovina,Bulgaria,Croatia,Cyprus,Czech Republic,Denmark,Estonia,Finland,France,Georgia,Germany,Greece,Hungary,Iceland,Ireland,Israel,Italy,Latvia,Liechtenstein,Lithuania,Luxembourg,Macedonia,Malta,Moldova,Monaco,Montenegro,Netherlands,Norway,Poland,Portugal,Romania,San Marino,Serbia,Slovakia,Slovenia,Spain,Sweden,Switzerland,Turkey,Ukraine,United Kingdom,Vatican City,Algeria,Angola,Benin,Botswana,Burkina,Burundi,Cameroon,Cape Verde,Central African Republic,Chad,Comoros,Democratic Republic of Congo,Djibouti,Egypt,Equatorial Guinea,Eritrea,Ethiopia,Gabon,Gambia,Ghana,Guinea,Guinea-Bissau,Ivory Coast,Kenya,Lesotho,Liberia,Libya,Madagascar,Malawi,Mali,Mauritania,Mauritius,Morocco,Mozambique,Namibia,Niger,Nigeria,Rwanda,Sao Tome and Principe,Senegal,Seychelles,Sierra Leone,Somalia,South Africa,Swaziland,Tanzania,Togo,Tunisia,Uganda,Zambia,Zimbabwe,Antigua and Barbuda,Bahamas,Barbados,Belize,Canada,Costa Rica,Dominica,Dominican Republic,El Salvador,Grenada,Guatemala,Haiti,Honduras,Jamaica,Mexico,Nicaragua,Panama,Saint Kitts and Nevis,Saint Lucia,Saint Vincent and the Grenadines,Trinidad and Tobago,United States,Argentina,Bolivia,Brazil,Chile,Colombia,Ecuador,Guyana,Paraguay,Peru,Suriname,Uruguay,Venezuela,Australia,Fiji,Kiribati,Marshall Islands,Micronesia,Nauru,New Zealand,Palau,Papua New Guinea,Samoa,Solomon Islands,Tonga,Tuvalu,Vanuatu STSW-SRTC002
ActiveSPI code -Serial RTC
Clocks and timers software ST
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All resources
Resource title | Version | Latest update |
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Product Specifications (1)
Resource title | Version | Latest update | ||
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19.0 | 09 Apr 2024 | 09 Apr 2024 |
Application Notes (5 of 11)
Resource title | Version | Latest update | ||
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3.0 | 13 Sep 2018 | 13 Sep 2018 | ||
4.0 | 15 Feb 2015 | 15 Feb 2015 | ||
2.1 | 03 Apr 2013 | 03 Apr 2013 | ||
4.1 | 31 Oct 2024 | 31 Oct 2024 | ||
2.0 | 31 Oct 2024 | 31 Oct 2024 | ||
1.0 | 14 May 2015 | 14 May 2015 | ||
4.0 | 31 Oct 2024 | 31 Oct 2024 | ||
2.0 | 03 Apr 2013 | 03 Apr 2013 | ||
2.0 | 10 Oct 2022 | 10 Oct 2022 | ||
4.1 | 10 Oct 2022 | 10 Oct 2022 | ||
1.2 | 04 Sep 2015 | 04 Sep 2015 |
Brochures (2)
Resource title | Version | Latest update | ||
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1.0 | 09 Jun 2023 | 09 Jun 2023 | ||
2.0 | 01 Aug 2015 | 01 Aug 2015 |
Product Certifications (1)
Resource title | Version | Latest update | ||
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1.0 | 10 Feb 2025 | 10 Feb 2025 |
EDA Symbols, Footprints and 3D Models
STMicroelectronics - M41T83
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Symbols

Footprints

3D models
All resources
Resource title | Version | Latest update |
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IBIS models (1)
Resource title | Version | Latest update | ||
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ZIP | 1.0 | 13 Jan 2016 | 13 Jan 2016 |
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Quality and Reliability
Part Number | Marketing Status | Package | Grade | RoHS Compliance Grade | Material Declaration** |
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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 |
Marketing Status
Package
SO18 with embedded crystal
Grade
Industrial
RoHS Compliance Grade
Ecopack1
Marketing Status
Package
VFQFPN 16 4x4x1.0
Grade
Industrial
RoHS Compliance Grade
Ecopack2
Marketing Status
Package
SO18 with embedded crystal
Grade
Industrial
RoHS Compliance Grade
Ecopack1
Marketing Status
Package
VFQFPN 16 4x4x1.0
Grade
Industrial
RoHS Compliance Grade
Ecopack2
Marketing Status
Package
SO18 with embedded crystal
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.
Sample & Buy
Part Number | Marketing Status | Budgetary Price (US$)*/Qty | Order from ST | Order from distributors | Package | Packing Type | RoHS | Country of Origin | ECCN (US) | ECCN (EU) | Operating temperature (°C) | Operating Temperature (°C) (max) | NVRAM size (B) | ||||||||||||||||||||||||||||||||||||
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min | max | ||||||||||||||||||||||||||||||||||||||||||||||||
M41T83SMY6F | Active | 2.2695 / 1k | Available at 2 distributors Distributor availability of M41T83SMY6F
Distributor reported inventory date: 4/1/2025 | | | | Buy from Distributor | | SO18 with embedded crystal | Tape and Reel | PHILIPPINES | EAR99 | NEC | -40 | 85 | 7 | |||||||||||||||||||||||||||||||||
M41T83ZMY6F | Active | 2.4695 / 1k | Available at 5 distributors Distributor availability of M41T83ZMY6F
Distributor reported inventory date: 4/1/2025 | | | | Buy from Distributor | | SO18 with embedded crystal | Tape and Reel | PHILIPPINES | EAR99 | NEC | -40 | 85 | 7 | |||||||||||||||||||||||||||||||||
M41T83RQA6F | Active | 1.6763 / 1k | Available at 2 distributors Distributor availability of M41T83RQA6F
Distributor reported inventory date: 4/1/2025 | | | | Buy from Distributor | | VFQFPN 16 4x4x1.0 | Tape and Reel | MALAYSIA | EAR99 | NEC | -40 | 85 | 7 | |||||||||||||||||||||||||||||||||
M41T83ZQA6F | Active | 1.6763 / 1k | Available at 1 distributors Distributor availability of M41T83ZQA6F
Distributor reported inventory date: 4/1/2025 | | | | Buy from Distributor | | VFQFPN 16 4x4x1.0 | Tape and Reel | MALAYSIA | EAR99 | NEC | -40 | 85 | 7 | |||||||||||||||||||||||||||||||||
M41T83SQA6F | Active | 1.6763 / 1k | Available at 4 distributors Distributor availability of M41T83SQA6F
Distributor reported inventory date: 4/1/2025 | | | | Buy from Distributor | | VFQFPN 16 4x4x1.0 | Tape and Reel | MALAYSIA | EAR99 | NEC | -40 | 85 | 7 | |||||||||||||||||||||||||||||||||
M41T83RMY6F | Active | 2.3695 / 1k | Available at 5 distributors Distributor availability of M41T83RMY6F
Distributor reported inventory date: 4/2/2025 | | | | Buy from Distributor | | SO18 with embedded crystal | Tape and Reel | PHILIPPINES | EAR99 | NEC | -40 | 85 | 7 |
M41T83SMY6F Active
Part Number:
M41T83SMY6F
Operating Temperature (°C)
Min:
-40
Max:
85
NVRAM size (B):
7
MOUSER
Stock
2550Min.Order
1DIGIKEY
Stock
1335Min.Order
1Distributor reported inventory date: 4/1/2025
Stock
Min.Order
M41T83ZMY6F Active
Part Number:
M41T83ZMY6F
Operating Temperature (°C)
Min:
-40
Max:
85
NVRAM size (B):
7
Farnell Element14
Stock
440Min.Order
1MOUSER
Stock
1081Min.Order
1FUTURE
Stock
1000Min.Order
0DIGIKEY
Stock
1865Min.Order
1Newark Element14
Stock
40Min.Order
0Distributor reported inventory date: 4/1/2025
Stock
Min.Order
M41T83RQA6F Active
Part Number:
M41T83RQA6F
Operating Temperature (°C)
Min:
-40
Max:
85
NVRAM size (B):
7
MOUSER
Stock
7204Min.Order
1DIGIKEY
Stock
2956Min.Order
1Distributor reported inventory date: 4/1/2025
Stock
Min.Order
M41T83ZQA6F Active
Part Number:
M41T83ZQA6F
Operating Temperature (°C)
Min:
-40
Max:
85
NVRAM size (B):
7
DIGIKEY
Stock
1101Min.Order
1Distributor reported inventory date: 4/1/2025
Stock
Min.Order
M41T83SQA6F Active
Part Number:
M41T83SQA6F
Operating Temperature (°C)
Min:
-40
Max:
85
NVRAM size (B):
7
MOUSER
Stock
4730Min.Order
1FUTURE
Stock
20000Min.Order
0AVNET
Stock
39000Min.Order
0DIGIKEY
Stock
1619Min.Order
1Distributor reported inventory date: 4/1/2025
Stock
Min.Order
M41T83RMY6F Active
Part Number:
M41T83RMY6F
Operating Temperature (°C)
Min:
-40
Max:
85
NVRAM size (B):
7
Farnell Element14
Stock
4204Min.Order
1MOUSER
Stock
562Min.Order
1FUTURE
Stock
6000Min.Order
0DIGIKEY
Stock
7375Min.Order
1YOSUN
Stock
100Min.Order
1Distributor reported inventory date: 4/2/2025
Stock
Min.Order
(*) Suggested Resale Price (USD) per defined quantity for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office or our Distributors