Overview
The M41T82RM6E is a low-power serial I²C real-time clock (RTC) manufactured by STMicroelectronics. This device is part of the M41T8x family, which includes the M41T82 and M41T83 models. The M41T82RM6E features a built-in 32.768 kHz oscillator, which can be external crystal-controlled for the SO8 package. It is designed to provide accurate timekeeping with minimal power consumption, making it suitable for applications requiring long battery life.
The device includes a non-volatile, time-of-day clock/calendar, two alarm interrupts, a watchdog timer, a programmable 8-bit counter, and square wave outputs. It also features automatic switchover to a battery supply during power failures, ensuring continuous operation.
Key Specifications
| Parameter | Value |
|---|---|
| Operating Voltage | 2.0 V to 5.5 V |
| Battery Supply Current | 365 nA |
| Accuracy | ±5 ppm typical after 2 reflows (SOX18) |
| Operating Temperature | –40 °C to 85 °C |
| Package Options | 8-lead SOIC (M41T82) |
| Serial Interface | I²C bus (400 kHz protocol) |
| Counters | Tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century |
| User SRAM | 7 bytes of battery-backed user SRAM |
| RoHS Compliance | Lead-free components compliant with the RoHS directive |
Key Features
- Ultra-low battery supply current of 365 nA
- Factory-calibrated accuracy of ±5 ppm typical after 2 reflows (SOX18)
- Much better accuracies achievable using built-in programmable analog and digital calibration circuits
- Counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century
- Automatic switchover and reset output circuitry (fixed reference)
- Serial interface supports I²C bus (400 kHz protocol)
- Programmable alarm with interrupt function (valid even during battery backup mode)
- Optional 2nd programmable alarm available
- Square wave output defaults to 32 KHz on power-up (M41T83 only)
- RESET (RST) output
- Watchdog timer
- Programmable 8-bit counter/timer
- Battery low flag
- Low operating current of 80 μA
- Oscillator stop detection
- Battery or SuperCap™ backup
Applications
The M41T82RM6E is suitable for a variety of applications that require accurate timekeeping and low power consumption. These include:
- Consumer electronics such as smart home devices and wearables
- Industrial automation systems
- Medical devices requiring precise timing
- Automotive systems where reliable timekeeping is crucial
- Battery-powered devices where long battery life is essential
Q & A
- What is the operating voltage range of the M41T82RM6E?
The operating voltage range is 2.0 V to 5.5 V.
- What is the typical battery supply current of the M41T82RM6E?
The typical battery supply current is 365 nA.
- What is the accuracy of the M41T82RM6E after 2 reflows?
The accuracy is ±5 ppm typical after 2 reflows (SOX18 package).
- What types of counters are available on the M41T82RM6E?
The device includes counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century.
- Does the M41T82RM6E support I²C communication?
Yes, it supports I²C bus (400 kHz protocol).
- What is the purpose of the automatic switchover feature?
The automatic switchover feature switches to the battery supply during power failures to ensure continuous operation.
- Is the M41T82RM6E RoHS compliant?
Yes, the device is RoHS compliant with lead-free components.
- What is the operating temperature range of the M41T82RM6E?
The operating temperature range is –40 °C to 85 °C.
- Does the M41T82RM6E have user SRAM?
Yes, it has 7 bytes of battery-backed user SRAM.
- What is the purpose of the watchdog timer?
The watchdog timer is used to monitor the system and reset it if it fails to respond within a specified time.
