Overview
The M41T00, produced by STMicroelectronics, is a low power serial real-time clock (RTC) with a built-in 32.768 kHz oscillator that is external crystal controlled. This device is designed to provide accurate timekeeping and is particularly useful in applications requiring reliable clock functions even during power failures. The M41T00 uses eight bytes of RAM for the clock/calendar function, configured in binary-coded decimal (BCD) format, and communicates via a two-line bidirectional I2C bus. It features automatic switchover to a battery supply during power failures, ensuring data retention for over 5 years with a small lithium coin cell.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Operating Voltage | 2.0 to 5.5 | V |
| Battery Supply Current | 0.8 μA (typ at 3 V) | μA |
| Oscillator Frequency | 32.768 kHz | kHz |
| Load Capacitance | 12.5 pF | pF |
| Operating Temperature | -40 to 85 | °C |
| Package Type | 8-lead plastic small outline package (SO-8) | |
| Data Retention Time | In excess of 5 years with a 50 mA/h 3 V lithium cell | |
| Serial Interface | I2C bus (100 kHz protocol) |
Key Features
- Counters for seconds, minutes, hours, day, month, years, and century
- 32 kHz crystal oscillator integrating load capacitance (12.5 pF) for exceptional oscillator stability
- Serial interface supports I2C bus (100 kHz protocol)
- Ultra low battery supply current of 0.8 μA (typ at 3 V)
- Automatic switchover and deselect circuitry during power failures
- Software clock calibration to compensate for crystal deviation due to temperature
- Automatic leap year compensation
- Operating temperature range of -40 to 85 °C
Applications
The M41T00 is suitable for a variety of applications where accurate timekeeping is crucial, including industrial automation, medical devices, consumer electronics, and any system requiring reliable clock functions. It is particularly useful in scenarios where power failures are common, as it ensures continuous operation using a battery backup.
Q & A
- What is the primary function of the M41T00?
The M41T00 is a low power serial real-time clock (RTC) designed to provide accurate timekeeping. - What type of oscillator does the M41T00 use?
The M41T00 uses a 32.768 kHz crystal oscillator. - What is the operating voltage range of the M41T00?
The operating voltage range is 2.0 to 5.5 V. - How does the M41T00 handle power failures?
The M41T00 automatically switches to a battery supply during power failures to maintain clock operations. - What is the typical battery supply current of the M41T00?
The typical battery supply current is 0.8 μA at 3 V. - What type of serial interface does the M41T00 support?
The M41T00 supports the I2C bus with a 100 kHz protocol. - What is the operating temperature range of the M41T00?
The operating temperature range is -40 to 85 °C. - How long can the M41T00 retain data with a lithium coin cell?
The M41T00 can retain data for over 5 years with a 50 mA/h 3 V lithium cell. - Does the M41T00 support software clock calibration?
Yes, the M41T00 supports software clock calibration to compensate for crystal deviation due to temperature. - Is the M41T00 suitable for industrial applications?
Yes, the M41T00 is suitable for industrial applications due to its robust features and wide operating temperature range.
