STMicroelectronics M41T62LC6F

Overview

M41T62LC6F from STMicroelectronics is an ultra-compact, embedded-crystal real-time clock (RTC) IC with integrated 32.768 kHz oscillator, I²C interface, alarm interrupt, and programmable square wave output. It delivers ±2 ppm software calibration, 350 nA timekeeping current at 3 V, and operates down to 1.0 V - enabling long-life battery-backed timekeeping in space-constrained industrial and portable systems.

For engineers reviewing the M41T62LC6F datasheet, M41T62LC6F pinout, M41T62LC6F application, or M41T62LC6F equivalent, key selection criteria include its LCC8 package with embedded crystal (no external components), 1.5 × 3.2 mm footprint, 32 kHz SQW default-on power-up behavior, oscillator fail detection, and support for leap-year compensation and century register handling.

Technical Context

The M41T62LC6F implements a binary-coded decimal (BCD) RTC core with eight clock/calendar registers (tenths/hundredths of second through century), updated via a dual-buffer architecture that freezes time during I²C reads to prevent mid-transfer rollover. Its on-chip oscillator integrates load capacitors and supports high-series-resistance crystals, with stop-detection logic monitoring oscillation integrity.

It functions as an I²C slave (address 0xD0) with automatic address pointer increment, supporting sequential read/write of all 16 registers. Alarm functionality includes repeat modes (RPT1–RPT5), enable/disable control (AFE), and flag reporting (AF), while the SQW output is programmable from 1 Hz to 32 kHz and defaults to 32 kHz open-drain output on power-up.

Key Specifications

Pinout & Package

Package: 8-pin LCC (1.5 × 3.2 mm), lead-free and halogen-free (ECOPACK2). Crystal is fully embedded; XI and XO pins are not bonded and must be left unconnected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS3231SN#T&R and M41T81SM6F, the M41T62LC6F uniquely balances ultra-miniaturization (1.5 × 3.2 mm), zero-external-component timekeeping, and sub-µA power - making it optimal for size- and battery-limited edge devices where factory calibration suffices.

Availability

M41T62LC6F is available at Aetrix Electronics and suitable for smart metering, industrial data logging, medical wearables, and asset tracking requiring stable component supply, long lifecycle assurance, and consistent ECOPACK2 compliance.

Supply support for M41T62LC6F 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 sensing solutions for industrial, automotive, and consumer markets.

The M41T62LC6F belongs to ST's low-power serial RTC product line, engineered specifically for space-constrained, battery-operated systems demanding high accuracy, minimal external components, and robust operation across extended temperature ranges.

FAQ

Does M41T62LC6F require external load capacitors for the crystal?

No. The M41T62LC6F uses an embedded 32.768 kHz crystal with integrated load capacitance (12.5 pF typical), eliminating all external capacitors and associated PCB routing. This is confirmed in the DS3840 datasheet Section 1 and Figure 4, which explicitly states "XI and XO are not bonded on LCC package" and lists "no external oscillator components required" as a key feature.

What is the maximum I²C clock frequency supported?

The M41T62LC6F supports standard-mode I²C up to 400 kHz, as specified in the "Features" section and verified in Section 2.1 of DS3840 Rev 24. It does not support fast-mode (1 MHz) or high-speed mode; attempting higher frequencies may result in communication failures or register corruption.

Can the SQW output be disabled after power-up?

Yes. The SQW output is enabled by default at power-up but can be disabled by clearing the SQWE bit (bit 7 of register 0Ah) via I²C write. Disabling SQW reduces active current draw and prevents unintended clocking of downstream logic - a capability documented in Table 3 (M41T62 register map) and Section 3.1.

How does oscillator fail detection work?

Oscillator fail detection monitors internal oscillator activity and sets the OF (oscillator fail) bit in register 0Fh when oscillation stops. When OFIE (bit 7 of register 02h) is set, this condition also asserts the IRQ/OUT pin low. The function is hardware-implemented and requires no firmware polling - detailed in Section 3.11 and Table 3 of DS3840.