STMicroelectronics M41T11M6F

Overview

M41T11M6F from STMicroelectronics is a serial real-time clock (RTC) IC with integrated 32.768 kHz crystal oscillator, 56 bytes of NVRAM, I²C interface (100 kHz), ultra-low battery current (0.8 μA typ.), and automatic VCC-to-VBAT switchover - used for timekeeping and data retention in industrial control panels, point-of-sale terminals, and network infrastructure equipment.

For engineers reviewing the M41T11M6F datasheet, M41T11M6F pinout, M41T11M6F application, or M41T11M6F equivalent, this page delivers verified technical context, validated pin functions, confirmed I²C timing compliance, calibrated RTC accuracy specs, and real-world use cases requiring long-term battery-backed timekeeping without external trim components.

Technical Context

The M41T11M6F implements a binary-coded decimal (BCD) clock/calendar engine with automatic leap-year compensation and century-bit handling via dedicated CE/CT bits in the hours register. Its on-die oscillator integrates 12.5 pF load capacitance, enabling stable operation with high-series-resistance crystals up to 70 kΩ.

It operates as an I²C slave device with fixed 7-bit address 0xD0 (1101000b), supports sequential and random-access reads/writes across 64-byte memory space (8 registers + 56 NVRAM bytes), and features hardware-controlled power-fail detection that triggers immediate VBAT takeover when VCC drops below VSO (typ. 2.0 V).

Key Specifications

Pinout & Package

Package: 8-lead SOIC (SO8), 150-mil body width, RoHS-compliant lead-free finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RTC applications.

Compared with DS1307+ and PCF8563, the M41T11M6F uniquely combines integrated 12.5 pF oscillator loading, software calibration, and hardware century management - making it optimal for industrial systems demanding field-deployed accuracy, minimal BOM, and multi-century calendar reliability.

Availability

M41T11M6F is available at Aetrix Electronics and suitable for industrial control panels, network infrastructure logging, point-of-sale terminals, and smart energy metering requiring stable component supply with full lifecycle support.

Supply support for M41T11M6F 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 sensor solutions for industrial, automotive, and consumer markets.

The M41T11 belongs to ST's real-time clock product line, engineered specifically for robust, low-power, battery-backed timekeeping in industrial and infrastructure applications where long-term accuracy and field reliability are mandatory.

FAQ

What crystal specifications are required for the M41T11M6F?

The M41T11M6F requires a standard 32.768 kHz tuning-fork crystal with series resistance ≤70 kΩ and load capacitance matched to its internal 12.5 pF. No external capacitors are needed. Crystals rated for –40°C to +85°C operation ensure full-spec performance across the device's temperature range.

Does the M41T11M6F support I²C clock stretching?

No, the M41T11M6F does not implement clock stretching. It adheres strictly to standard I²C timing: SCL high/low periods ≥4 µs and ≥4.7 µs respectively, with data setup/hold times meeting 250 ns and 0 ns requirements. Master controllers must observe these limits without expecting slave-induced delays.

How is the century bit managed during year-2100 rollover?

The M41T11M6F uses dedicated Century Enable (CEB) and Century (CB) bits in the hours register. When CEB = 1, CB toggles automatically at century boundaries (e.g., 2099→2100). This hardware logic ensures correct BCD interpretation of years 2000–2099 vs. 2100–2199 without firmware intervention.

Can the FT/OUT pin drive an LED directly?

Yes - the FT/OUT pin is an open-drain output rated for 3 mA sink current. With a 3.3 V supply and 1 kΩ series resistor, it can drive a standard green LED at ~2 mA for visual status indication. The pin outputs 1 Hz by default, configurable via control register to 32.768 kHz if needed.