STMicroelectronics M41T83SMY6E

Overview

M41T83SMY6E from STMicroelectronics is an I²C real-time clock (RTC) with embedded 32.768 kHz crystal in SOX18 package, providing battery-backed timekeeping, dual alarms, watchdog timer, 8-bit counter/timer, and 7-byte SRAM. It delivers ±5 ppm factory-calibrated accuracy after two reflows, ultra-low 365 nA battery current, and operates from –40 °C to +85 °C for industrial backup timing in power-loss-critical systems.

For engineers reviewing the M41T83SMY6E datasheet, M41T83SMY6E pinout, M41T83SMY6E application, or M41T83SMY6E equivalent, this page details its embedded-crystal RTC architecture, switchover behavior at VCC = 3.00–5.50 V, SQW output defaults, IRQ1/FT/OUT priority logic in backup mode, and OTP bit support exclusive to SOX18 packaging.

Technical Context

The M41T83SMY6E implements a fully autonomous RTC core with BCD-encoded calendar registers (century, year, month, date, day, hour, minute, second, tenths/hundredths), automatic leap-year correction, and oscillator fail detection. Its embedded crystal eliminates external load capacitor tuning and reduces board footprint versus QFN16/SO8 variants.

It features dual interrupt outputs (IRQ1/FT/OUT and IRQ2), programmable square wave (default 32 kHz), RST open-drain reset output, and analog/digital calibration circuits enabling post-assembly accuracy optimization. The device uses VRST/VSO = 2.93 V as fixed switchover threshold and supports I²C up to 400 kHz.

Key Specifications

Pinout & Package

Package: SOX18 (18-lead plastic small outline, 300 mils, embedded crystal, 11.61 mm × 7.62 mm).

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS3231SN#T&R, M41T83SMY6E trades absolute accuracy for lower power and zero-layout crystal integration; compared with M41T82M6E, it adds embedded timing, SQW, and IRQ1/FT/OUT flexibility at the cost of larger SOX18 footprint and higher minimum VCC.

Availability

M41T83SMY6E is available at Aetrix Electronics and suitable for smart metering, industrial PLCs, medical infusion pumps, and building HVAC controllers requiring stable component supply with guaranteed long-term availability and RoHS-compliant packaging.

Supply support for M41T83SMY6E 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 microcontrollers, power ICs, sensors, and timing solutions for industrial, automotive, and consumer markets.

The M41T8x product line targets cost-optimized, high-reliability RTC applications where embedded crystal integration, ultra-low battery current, and dual-alarm interrupt capability are essential - especially in space-constrained industrial and medical devices.

FAQ

What is the function of the DU pin on M41T83SMY6E?

The DU (Do-Not-Use) pin is internally tied to VCC and must be externally connected to the main supply rail. Leaving it floating or grounding it may cause undefined behavior, including incorrect switchover thresholds or oscillator instability. This requirement is unique to the SOX18 package variant and is documented in Figure 5 and Table 1 of the official datasheet.

Does M41T83SMY6E support I²C clock stretching?

Yes - the M41T83SMY6E supports I²C clock stretching during register read/write operations to accommodate slower hosts. The device holds SCL low until internal processing completes, ensuring data coherency without host-side timeout errors. This behavior is inherent to its slave-mode I²C implementation and verified in Section 2.2 (Read Mode) and Figure 13 of the datasheet.

How does the embedded crystal in SOX18 affect reflow profile compatibility?

The SOX18 package's embedded crystal is qualified for standard lead-free reflow profiles (J-STD-020, peak 260 °C). ST specifies that the ±5 ppm accuracy rating applies after two reflows, confirming full compatibility with typical PCB assembly processes. No special pre-baking or slow-ramp profiles are required beyond standard moisture sensitivity level (MSL) 3 handling.

Can the SQW output be disabled or configured as a general-purpose I/O?

No - the SQW pin is dedicated to square wave output and cannot be repurposed as a general-purpose I/O. It defaults to 32 kHz on power-up and is programmable only to 1 Hz, 2 Hz, 4 Hz, or 8 Hz via the SQWE bit. There is no register-controlled tri-state or alternate function mode; disabling requires clearing SQWE and leaving the pin unconnected or pulled high via external resistor.