Overview
The M41T81M6E is a low-power serial Real-Time Clock (RTC) integrated circuit manufactured by STMicroelectronics. It is designed to provide precise timekeeping and calendar functions. The device features a built-in 32.768 kHz oscillator controlled by an external crystal, ensuring high oscillator stability. It operates as a slave device on a two-line, bidirectional I2C interface, allowing for serial access to its clock and calendar data. The M41T81M6E also includes automatic power failure detection and switchover to a battery supply, making it suitable for applications requiring continuous timekeeping even during power outages.
Key Specifications
| Parameter | Description |
|---|---|
| Operating Voltage | 2.0 to 5.5 V |
| Battery Supply Current | 0.6 μA (typ at 3 V) |
| Oscillator Frequency | 32.768 kHz |
| Load Capacitance | 12.5 pF |
| Serial Interface | I2C bus (400 kHz protocol) |
| Operating Temperature | –40 to 85 °C |
| Package Type | 8-pin SOIC |
| RoHS Compliance | Ecopack3 |
Key Features
- Counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century in 24-hour BCD format
- Automatic corrections for 28, 29 (leap year - valid until year 2100), 30, and 31 day months
- 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
- Power-down time stamp (HT bit) allowing determination of time elapsed in battery backup
- Programmable square wave output
- Automatic switchover and deselect circuitry for power failure detection
- ECOPACK® package available
Applications
The M41T81M6E is suitable for a variety of applications that require precise timekeeping and calendar functions, including:
- Industrial control systems
- Medical devices
- Automotive systems
- Consumer electronics
- Smart home devices
- IoT devices requiring real-time clock functionality
Q & A
- What is the operating voltage range of the M41T81M6E?
The operating voltage range is 2.0 to 5.5 V.
- What is the typical battery supply current of the M41T81M6E?
The typical battery supply current is 0.6 μA at 3 V.
- What type of serial interface does the M41T81M6E use?
The M41T81M6E uses an I2C bus with a 400 kHz protocol.
- What is the operating temperature range of the M41T81M6E?
The operating temperature range is –40 to 85 °C.
- Does the M41T81M6E have automatic power failure detection?
- What types of counters are available in the M41T81M6E?
The device includes counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century.
- Can the M41T81M6E be calibrated for temperature variations?
- What is the purpose of the watchdog timer in the M41T81M6E?
The watchdog timer is programmable and can be set from 62.5 ms to 128 s to monitor system activity and reset the system if necessary.
- Is the M41T81M6E RoHS compliant?
- What package type is the M41T81M6E available in?
The M41T81M6E is available in an 8-pin SOIC package.
