Overview
The M41T81SM6E is a low-power serial real-time clock (RTC) manufactured by STMicroelectronics. This device is designed to provide accurate time-keeping and calendar functions, along with several additional features such as alarms, watchdog timers, and programmable square wave outputs. The M41T81SM6E operates using a 32.768 kHz oscillator, which is external crystal controlled, ensuring high stability and reliability. It supports an I2C bus interface with a 400 kHz protocol, making it versatile for various applications. The device is available in an 8-pin SOIC package and is suitable for use in a wide range of temperatures from –40 to 85 °C.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Operating Voltage | 2.0 to 5.5 | V |
| Battery Supply Current | 0.6 | μA (typ at 3 V) |
| Oscillator Frequency | 32.768 | kHz |
| Interface | I2C (400 kHz protocol) | |
| Operating Temperature | –40 to 85 | °C |
| Package Type | 8-pin SOIC | |
| Load Capacitance | 12.5 | pF |
Key Features
- Counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century in 24-hour BCD format.
- 32 KHz crystal oscillator with integrated load capacitance (12.5 pF) for exceptional oscillator stability.
- Serial interface supporting I2C bus (400 kHz protocol).
- Ultra-low battery supply current of 0.6 μA (typ at 3 V).
- Automatic switchover and deselect circuitry for full operation in 3.0 V applications.
- Power-down time-stamp (HT bit) to determine time elapsed in battery backup.
- Programmable alarm and interrupt function, valid even during battery backup mode.
- Accurate programmable watchdog timer (from 62.5 ms to 128 s).
- Software clock calibration to compensate for crystal deviation due to temperature.
- Operating temperature range of –40 to 85 °C.
Applications
The M41T81SM6E is suitable for a variety of applications where accurate time-keeping and low power consumption are critical. These include:
- Consumer electronics such as smart home devices, wearables, and handheld gadgets.
- Industrial automation systems requiring precise timing and low power operation.
- Medical devices that need reliable and accurate time-keeping functions.
- Automotive systems, especially those requiring battery backup during power failures.
- IoT devices that need to maintain time accuracy over extended periods.
Q & A
- What is the operating voltage range of the M41T81SM6E?
The operating voltage range is from 2.0 to 5.5 V.
- What type of interface does the M41T81SM6E support?
The device supports an I2C bus interface with a 400 kHz protocol.
- What is the typical battery supply current of the M41T81SM6E?
The typical battery supply current is 0.6 μA at 3 V.
- What is the frequency of the oscillator in the M41T81SM6E?
The oscillator frequency is 32.768 kHz.
- Does the M41T81SM6E support automatic switchover to battery during power failure?
Yes, it supports automatic switchover and deselect circuitry for full operation in 3.0 V applications.
- What is the operating temperature range of the M41T81SM6E?
The operating temperature range is from –40 to 85 °C.
- Can the M41T81SM6E be calibrated for crystal deviation due to temperature?
Yes, it supports software clock calibration to compensate for crystal deviation due to temperature.
- What types of packages are available for the M41T81SM6E?
The device is available in an 8-pin SOIC package.
- Does the M41T81SM6E have a programmable watchdog timer?
Yes, it has an accurate programmable watchdog timer ranging from 62.5 ms to 128 s.
- Is the M41T81SM6E RoHS compliant?
Yes, the M41T81SM6E is RoHS compliant.
