STMicroelectronics M41T00M6F

Overview

M41T00M6F from STMicroelectronics is a serial real-time clock (RTC) IC with integrated 32.768 kHz crystal oscillator, I²C interface (100 kHz), ultra-low battery current (0.8 μA typ at 3 V), and automatic power switchover between V_CC and V_BAT. It maintains BCD-formatted time/date registers (seconds to century), supports software calibration, and operates across –40 to +85 °C in industrial metering and backup power systems.

For engineers reviewing the M41T00M6F datasheet, M41T00M6F pinout, M41T00M6F application, or M41T00M6F equivalent, this page delivers verified technical context, validated pin functions, confirmed I²C timing compliance, and calibrated RTC accuracy data - all directly traceable to ST's production datasheet DocID6100 Rev 10.

Technical Context

The M41T00M6F implements a slave-mode I²C interface with fixed 7-bit address 0xD0h, supporting sequential read/write of eight BCD registers (time/date/control). Its on-chip oscillator integrates 12.5 pF load capacitance and tolerates high-series-resistance crystals for stable operation under thermal stress.

Power management includes voltage-sense circuitry that triggers automatic switchover to V_BAT when V_CC drops below V_SO (VBAT − 0.50 V typ), entering ultra-low-current retention mode. Clock calibration uses a 5-bit signed value (±0 to ±31) applied every 64 minutes to adjust oscillator count at the ÷256 stage, enabling ±2 ppm accuracy at 25 °C.

Key Specifications

Pinout & Package

Supplied in an 8-lead plastic small outline (SO8) package, 150 mils body width, compliant with JEDEC MS-012.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar real-time clock applications.

Compared with DS1307+, the M41T00M6F delivers superior oscillator stability via integrated 12.5 pF load and field-adjustable calibration; versus M41T00S, it trades minor V_SO margin for full backward compatibility in legacy 5 V industrial installations.

Availability

M41T00M6F is available at Aetrix Electronics and suitable for smart energy metering, industrial HMI systems, point-of-sale terminals, and medical infusion pumps requiring stable component supply across long product lifecycles.

Supply support for M41T00M6F includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MCU, power, and timing solutions for industrial, automotive, and consumer markets.

The M41T00 series targets cost-sensitive, battery-backed timing applications where precision, low power, and minimal external components are essential - especially in utility infrastructure and embedded control systems.

FAQ

What is the function of the FT/OUT pin on the M41T00M6F?

The FT/OUT pin is an open-drain output that provides either a 1 Hz square wave (for timekeeping verification) or the raw 32.768 kHz crystal frequency (for oscillator diagnostics). It requires an external pull-up resistor and is disabled during I²C communication to avoid bus contention. Its dual-mode capability supports both functional validation and production test workflows without additional test equipment.

Does the M41T00M6F require external load capacitors for the crystal?

No. The M41T00M6F integrates 12.5 pF load capacitance internally, eliminating the need for external capacitors. This simplifies PCB layout, reduces component count, and improves oscillator stability across temperature and board parasitics. External capacitors must not be added, as they would detune the oscillator and degrade accuracy or prevent startup.

How does the M41T00M6F handle leap years and month-end rollovers?

The M41T00M6F performs automatic leap year compensation in hardware using its BCD-encoded date registers. It correctly advances from February 28 to March 1 in common years and from February 29 to March 1 in leap years, including century boundary rules (e.g., 2000 is a leap year; 1900 is not). Month-end rollovers (e.g., April 30 → May 1) are also handled autonomously without firmware intervention.

What happens during a power transition from V_CC to V_BAT?

When V_CC falls below the switchover threshold (VBAT − 0.50 V typ), the M41T00M6F terminates any active I²C transaction, resets its internal address pointer, and enters ultra-low-power retention mode within 10 μs. All registers and RAM retain state. Upon V_CC recovery above V_SO, the device resumes normal operation without reset - preserving time continuity and eliminating timestamp gaps.