Overview
The M41T81SM6F is a low-power serial real-time clock (RTC) produced by STMicroelectronics. This component is designed to provide accurate time-keeping and various additional features, making it suitable for a wide range of applications. The M41T81SM6F integrates a 32.768 kHz oscillator, which is external crystal controlled, ensuring high stability and reliability. It supports an I2C bus interface with a protocol speed of up to 400 kHz, facilitating easy communication with other components in a system.
Key Specifications
| Specification | Value |
|---|---|
| Operating Voltage | 2.0 to 5.5 V |
| Battery Supply Current | 0.6 µA (typical) |
| Crystal Oscillator Frequency | 32.768 kHz |
| Interface | I2C bus (up to 400 kHz) |
| Package Options | 8-lead SOIC, 18-lead embedded crystal SOIC |
| Operating Temperature | –40 to 85 °C |
| SRAM | 20 bytes (8 bytes for clock/calendar, 12 bytes for status/control) |
| Alarm and Interrupt Functions | Programmable alarm and interrupt, valid even during battery backup mode |
| Watchdog Timer | Accurate programmable watchdog timer (from 62.5 ms to 128 s) |
Key Features
- Counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century in 24-hour BCD format.
- Integrated 32 kHz crystal oscillator with load capacitance (12.5 pF) for high stability.
- Oscillator stop detection and automatic switchover to battery supply during power failure.
- Ultra-low battery supply current and power-down time-stamp (HT bit) for determining time elapsed in battery backup.
- Battery low flag and programmable alarm and interrupt functions.
- Accurate programmable watchdog timer and software clock calibration for compensating crystal deviation due to temperature.
- Programmable square wave output.
Applications
The M41T81SM6F is suitable for various applications requiring accurate time-keeping and low power consumption, such as:
- Consumer electronics (e.g., smart home devices, wearables).
- Industrial control systems.
- Medical devices.
- Automotive systems.
- IoT devices.
Q & A
- What is the operating voltage range of the M41T81SM6F?
The operating voltage range is 2.0 to 5.5 V.
- What type of interface does the M41T81SM6F support?
The M41T81SM6F supports an I2C bus interface with a protocol speed of up to 400 kHz.
- What are the package options available for the M41T81SM6F?
The component is available in 8-lead SOIC and 18-lead embedded crystal SOIC packages.
- What is the typical battery supply current of the M41T81SM6F?
The typical battery supply current is 0.6 µA).
- Does the M41T81SM6F have programmable alarm and interrupt functions?
Yes, it has programmable alarm and interrupt functions, which are valid even during battery backup mode).
- What is the operating temperature range of the M41T81SM6F?
The operating temperature range is –40 to 85 °C).
- Does the M41T81SM6F support software clock calibration?
Yes, it supports software clock calibration to compensate for crystal deviation due to temperature).
- What is the purpose of the oscillator stop detection feature?
The oscillator stop detection feature monitors clock operation and ensures stability by detecting any oscillator stop).
- Can the M41T81SM6F operate with a small lithium button battery during power failure?
Yes, it can operate with a small lithium button battery during power failure, ensuring continuous time-keeping).
- Does the M41T81SM6F have a built-in power sense circuit?
Yes, it has a built-in power sense circuit that detects power failures and automatically switches to the battery supply).
