- Home
- Product Categories
cigen-M41T81
M41T81 semiconductor Series
stmI2C real-time clock ICs with calendar, alarm, and watchdog timer features
The M41T81 series from STMicroelectronics is a line of I2C real-time clock (RTC) integrated circuits designed for embedded systems that require precise timekeeping and scheduling capabilities. These ICs come equipped with a calendar function, alarm triggers, and a watchdog timer, making them ideal for applications that need to manage timing and ensure system stability.
If you're working on any project involving embedded systems, particularly those that require accurate time management, such as network equipment, industrial control systems, or automotive electronics, the M41T81 series could be a valuable addition. The calendar function allows for date and time tracking, while the alarm feature can be used for various timing events, from simple reminders to complex scheduling tasks. The watchdog timer is crucial for maintaining system integrity by resetting the microcontroller if it locks up or malfunctions.
One thing worth noting is that these ICs operate over a wide temperature range, typically from -40°C to +85°C, which makes them suitable for harsh environments. Engineers tend to reach for this when they need a reliable RTC solution that can handle diverse operational conditions without requiring external components for basic functionality.
Series Images (14)
Documents & Media
Frequently Asked Questions
M41T81 semiconductor - Part List
11 parts in total| Mfr Part # | Quantity Available | Price | Category | RoHS | Interface | Voltage - Supply | Packaging | Package / Case | Time Format | Operating Temperature | Mounting Type | Date Format | Standard Package | Memory | RAM Size | Voltage Rating | Voltage - Supply (Min) | Voltage - Supply, Battery | Number of Positions | Supplier Device Package | Type | Features | Bus Connection | Factory Pack Quantity | Standard Package Name | EU RoHS | Common Mode Transient Immunity (Min) | Width | Mounting Style | Package Quantity | Function | Other Names | Product Category | SVHC | Tariff No | Weight | Lead Style | Number of Pins | Material Finish | Length - Overall | Shell Size - Insert | Printed Circuit Board | Package Cooled | Termination | Mechanical Life | Height | Length | Size / Dimension | Programmable Features | MOQ | Unit Pack | Automotive | Leadfree Defin | Data Rate | Crystal AR | Power - Max | Voltage - Input (Min) | Matchcode | Standard Leadtime | Number of Outputs | Base Unit | Rad Hardened | DELETED | Operating Temperature - Junction | Spg | Number of Units | Product | Series | Manufacturer | Battery Series | Clock Frequency | Part Status | Reset Time | Memory Type | Connector Usage | Main Purpose | Display Units |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 M41T81M6F Real Time Clock Serial 20Byte 8-Pin SO N T/R IC RTC SERIAL W/ALARM 8-SOIC Real Time Clock Serial 512 (64x8) IC, RTC, I2C, W/ ALARM, 8-SO, REEL RTC circuit; I2C; 2÷5.5VDC; SO8 IC RTC CLK/CALENDAR I2C 8-SOIC 实时时钟 (RTC), 警报功能, 20B RAM, 串行总线, 2 → 5.5 V电源, 8针 SOIC封装 stmicroelectronics | 10 | 1: ¥10.99 | - | Lead free / RoHS Compliant | I²C, 2-Wire Serial | 2.5|3.3|5 V | Tape and Reel | 8SO N | HH:MM:SS:hh | -40 to 85 °C | Surface Mount | DW:DM:M:Y | Cut Tape | 20 B | 20 byte | 2 | 5.5 | 2.5 V ~ 3.5 V | 8 | 8-SO | RTC | Alarm, Leap Year, Square Wave Output, Watchdog Timer | Serial (I2C) | 2500 | SOIC | Compliant | Industrial | 4(Max) | SMD/SMT | SO N | Clock/Calendar/Alarm/Timer/Interrupt | 497-4709-2 | Real Time Clock | :No SVHC (20-Jun-2013) | 85423300 | 0.003 | Gull-wing | :8 | :MSL 1 - Unlimited | 5(Max) | 1.65(Max) | 8 | - | -40°C | - | - | - | - | - | 2500 | 2500 | NO | RoHS-conform | I2C | NO | 85°C | 2.0V | M41T81M6F | 15 weeks | - | - | - | - | - | 2500 | 1 | - | - | - | - | - | - | - | - | - | - | - |
 | 10 | 1: ¥25.97 | - | RoHS Compliant | Serial | 5.5 V | Tube | SO-28 | HH:MM:SS:hh | + 85 C | Surface Mount | YY-MM-DD-dd | 28 | 20 B | - | - | - | 2.5 V ~ 3.5 V | - | 8-SO | Clock/Calendar | Alarm, Leap Year, Square Wave Output, Watchdog Timer | - | 28 | - | - | - | - | SMD/SMT | - | Clock, Calendar, Alarm, Timer Interrupt | 497-2822-5 | - | - | - | - | - | - | - | - | - | - | - | - | Obsolete | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| 0 | - | No | Serial | 5.5 V | Reel | SO-28 | HH:MM:SS:hh | + 85 C | - | - | - | 20 B | - | - | - | - | - | - | - | - | - | 1000 | - | - | - | - | SMD/SMT | - | Clock, Calendar, Alarm, Timer Interrupt | - | Real Time Clock | - | - | - | - | - | - | - | - | - | - | - | Obsolete | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | |
M41T81M6 Real Time Clock USE 511-M41T81M6E M41T81M6, Real Time Clock, Alarm, Calendar, Clock, Watchdog Timer, 20B RAM, I2C, 2 to 5.5V, 8-Pin SOIC M41T81MQ6 STMicroelectronics | 10 | 1: ¥12.99 | - | No | Serial | 5.5 V | Tube | SO-8 | HH:MM:SS:hh | + 85 C | Surface Mount | DW:DM:M:Y | - | 20 B | 20B | 2 V | 5.5 V | - | 8 | - | - | - | Serial-I2C | 100 | - | - | - | 3.9mm | SMD/SMT | - | Clock, Calendar, Alarm, Timer Interrupt | - | - | - | - | - | - | - | - | - | - | - | SOIC | - | Obsolete | 1.25mm | 4.9mm | 4.9 x 3.9 x 1.25mm | Alarm, Battery Backup, Calendar, Chip Deselect, Clock, Switch Over, Watchdog Timer | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
 M41T81SMY6F Real Time Clock Serial 20Byte 18-Pin SOX T/R IC RTC SER W/ALARMS 18-SOIC Real Time Clock Serial Access Real Time Clock stmicroelectronics | 128 | 1: ¥79.56 | - | Lead free / RoHS Compliant | I²C, 2-Wire Serial | 3.3|5 V | Tape and Reel | 18SOX | HH:MM:SS:hh | -40 to 85 °C | Surface Mount | DW:DM:M:Y | Tape & Reel | 20 B | 20 byte | 2.7 | 5.5 | 2 V ~ 3.5 V | 18 | 18-SOX | Clock/Calendar | Alarm, Leap Year, Square Wave Output, Watchdog Timer | Serial (I2C) | 1000 | SOX | Compliant | Industrial | - | SMD/SMT | SOX | Clock/Calendar/Alarm/Timer/Interrupt | 497-6157-2 | Real Time Clock | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | Real Time Clocks | M41T81S | STMicroelectronics | Backup Switching | - | - | - | - | - | - | - |
M41T81SM6E Real Time Clock 2.0-5.5V 512 (64x8) Real Time Clock Serial 20Byte 8-Pin SO N Tube IC RTC SER ACCESS W/ALARM 8-SOIC IC, SERIAL RTC I2C, SMD, SO-8-8 IC RTC CLK/CALENDAR I2C 8-SOIC STMicroelectronics | 10 | 2000: ¥10.0758 | - | Lead free / RoHS Compliant | I²C, 2-Wire Serial | 2.7 V ~ 5.5 V | Tube | 8-SOIC (0.154", 3.90mm Width) | HH:MM:SS:hh | -40°C ~ 85°C | Surface Mount | DW:DM:M:Y | 100 | - | 20 | 2.7 | 5.5 | 2 V ~ 3.5 V | 8 | 8-SO | Clock/Calendar | Alarm, Leap Year, Square Wave Output, Watchdog Timer | Serial (I2C) | - | SOIC | Compliant | Industrial | 4(Max) | - | SO N | - | - | - | :No SVHC (20-Jun-2013) | 85423245 | 0.002 | Gull-wing | :8 | :- | 5(Max) | 1.65(Max) | 8 | - | :SMD | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | :1 | :41 | - | - | - | - | - | - | - | - | - | :32kHz | - | - | - | - | - | - |
M41T81M6E Real Time Clock Serial 512 (64x8) Real Time Clock Serial 20Byte 8-Pin SO N Tube IC RTC SERIAL W/ALARM 8-SOIC M41T81M6E, Real Time Clock, Alarm, Calendar, Clock, Watchdog Timer, 20B RAM, I2C, 2 to 5.5V, 8-Pin SOIC Year STMicroelectronics | 10 | 1: ¥12.99 | - | Lead free / RoHS Compliant | I²C, 2-Wire Serial | 2 V ~ 5.5 V | Tube | 8-SOIC (0.154", 3.90mm Width) | HH:MM:SS:hh | -40°C ~ 85°C | Surface Mount | DW:DM:M:Y | 100 | :20 x 8 | 20B | 2 V | 5.5 V | 2.5 V ~ 3.5 V | 8 | 8-SO | Clock/Calendar | Alarm, Leap Year, Square Wave Output, Watchdog Timer | Serial (I2C) | - | SOIC | Compliant | Industrial | 3.9mm | - | SO N | - | - | - | :No SVHC (20-Jun-2013) | 85423190 | 0.000001 | Gull-wing | :8 | :- | 5(Max) | 1.65(Max) | 8 | SOIC | - | - | 1.25mm | 4.9mm | 4.9 x 3.9 x 1.25mm | Alarm, Battery Backup, Calendar, Chip Deselect, Clock, Switch Over, Watchdog Timer | - | - | - | - | - | - | - | - | - | - | :1 | :41 | No | Compliant | 85C | - | - | - | - | - | - | - | :41T81 | :10Yr | :NVRAM | - | - | - |
M41T81SM6F Real Time Clock Serial 20Byte 8-Pin SO N T/R IC RTC SERIAL W/ALARM 8SOIC Real Time Clock 2.0-5.5V 512 (64x8) IC, RTC, I2C, W/ ALARM, 8-SO IC RTC CLK/CALENDAR I2C 8-SOIC 实时时钟 (RTC), 日历功能, 20B RAM, I2C总线, 2.7 → 5.5 V电源, 8针 SOIC封装 stmicroelectronics | 5000 | 2500: ¥9.3908 | - | Lead free / RoHS Compliant | I²C, 2-Wire Serial | 3.3|5 V | Tape and Reel | 8SO N | HH:MM:SS:hh | -40 to 85 °C | Surface Mount | DW:DM:M:Y | Tape & Reel | 20 B | 20 byte | 2.7 | 2.7 V | 2 V ~ 3.5 V | 8 | 8-SO | RTC | Alarm, Leap Year, Square Wave Output, Watchdog Timer | Serial (I2C) | 2500 | SOIC | Compliant | Industrial | 4(Max) | SMD/SMT | SO N | Clock/Calendar/Alarm/Timer/Interrupt | 497-4684-2 | Real Time Clock | :No SVHC (20-Jun-2013) | 85423300 | 0.003 | Gull-wing | :8 | :MSL 1 - Unlimited | 5(Max) | 1.65(Max) | 8 | SO N | -40°C | - | - | - | - | - | 2500 | 2500 | NO | RoHS-conform | I2C | NO | 85°C | 2.7V | M41T81SM6F | 15 weeks | - | - | No | Compliant | 85C | - | - | - | - | - | - | - | - | - | - | - | - | - |
M41T81SMY6E Real Time Clock Serial 20Byte 18-Pin SOX Tube IC RTC SER W/ALARMS 18-SOIC M41T81SMY6E, Real Time Clock, Alarm, Calendar, Clock, Watchdog Timer, 20B RAM, I2C, 2.7 to 5.5V, 18-Pin SOX RTC,M41T81SMY6E IC RTC CLK/CALENDAR I2C 18-SOIC STMicroelectronics | 10 | 1100: ¥17.7745 | - | Lead free / RoHS Compliant | I²C, 2-Wire Serial | 2.7 V ~ 5.5 V | Tube | 18-SOX, 18-SOIC with Crystal (7.5mm Width) | HH:MM:SS:hh | -40°C ~ 85°C | Surface Mount | DW:DM:M:Y | 44 | - | 20B | 2.7 V | 5.5 V | 2 V ~ 3.5 V | 18 | 18-SOX | Clock/Calendar | Alarm, Leap Year, Square Wave Output, Watchdog Timer | Serial (I2C) | - | SOX | Compliant | Industrial | 7.62mm | - | SOX | - | - | - | - | - | - | - | - | - | - | - | - | SOX | - | - | 2.34mm | 11.61mm | 11.61 x 7.62 x 2.34mm | Alarm, Battery Backup, Calendar, Chip Deselect, Clock, Switch Over, Watchdog Timer | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | I²C, 2-Wire Serial | Alarm, Leap Year, Square Wave Output, Watchdog Timer | YY-MM-DD-dd |
| 0 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | ||
| 0 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
