STMicroelectronics M41T83RMY6F

Overview

M41T83RMY6F from STMicroelectronics is a serial 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 operates from 2.7 V to 5.5 V, achieves ±5 ppm factory-calibrated accuracy after two reflows, and consumes only 365 nA in battery backup mode. Used in industrial control panels requiring long-term timestamping during main power loss.

For engineers reviewing the M41T83RMY6F datasheet, M41T83RMY6F pinout, M41T83RMY6F application, or M41T83RMY6F equivalent, key selection criteria include battery switchover threshold (2.63 V), embedded crystal integration (eliminating external XTAL layout), SQW output programmability, IRQ1/FT/OUT pin priority handling in backup mode, and OTP bit support for configuration locking in SOX18.

Technical Context

The M41T83RMY6F 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 I²C interface complies with 400 kHz Fast Mode timing, supports auto-incremented register addressing, and maintains data coherency via atomic read/write sequences.

Power management includes dual-voltage sensing (VSO = VRST = 2.63 V for R-grade), seamless VCC-to-VBAT switchover with reset assertion, and ultra-low 365 nA battery current enabling >10-year coin-cell operation. Calibration uses both analog (programmable load capacitance) and digital (periodic counter correction) methods, achieving <±2 ppm post-calibration stability over –40 °C to +85 °C.

Key Specifications

Pinout & Package

Package: SOX18 (18-lead plastic small outline, 300 mil, embedded crystal, 11.61 mm × 7.62 mm). Pin 1 marked by notch; Pins 2 & 3 and Pins 16 & 17 internally shorted; NF pins (1, 16, 17, 18) must be tied to VSS.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS3231SN#T&R, M41T83RMY6F trades ±2 ppm TCXO stability for integrated crystal and 4× lower battery current; versus M41T81M6F, it adds alarm 2, SQW output, and OTP configuration lock-enabling next-gen industrial timing without redesigning crystal layout.

Availability

M41T83RMY6F is available at Aetrix Electronics and suitable for industrial data loggers, medical infusion pumps, smart energy meters, and building automation controllers requiring stable component supply across extended product lifecycles.

Supply support for M41T83RMY6F 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 management ICs, sensors, and timing solutions for industrial, automotive, and consumer markets.

The M41T8x series targets cost-sensitive, high-reliability industrial timing applications where embedded crystal integration, ultra-low battery current, and dual-alarm scheduling are essential design requirements.

FAQ

What is the battery switchover voltage threshold for M41T83RMY6F?

The M41T83RMY6F uses VSO = VRST = 2.63 V for R-grade devices. When VCC drops below this threshold, the device automatically switches to VBAT, asserts RST, and continues RTC operation without time loss. This value is fixed and non-programmable, ensuring predictable behavior during brownout conditions.

Does M41T83RMY6F require external load capacitors for the embedded crystal?

No. The SOX18 package integrates a factory-tuned 32.768 kHz crystal with matched internal load capacitance. No external capacitors are needed-unlike QFN16 or SO8 variants-which simplifies layout, eliminates tuning effort, and improves production yield.

How is the century bit implemented in the M41T83RMY6F calendar register?

The century is encoded in bits CB1:CB0 of the century/hours register (address 0x03). These two bits form a binary counter tracking 100-year cycles (00 = 20xx, 01 = 21xx, 10 = 22xx, 11 = 23xx), enabling correct Y2K+100 date rollover through year 2399 without software intervention.

Can the SQW output be disabled or reconfigured after power-up?

Yes. The SQW output is controlled by the SQWE bit (bit 7 of register 0x0E). Writing '0' disables the output driver; writing '1' enables it. Frequency is selected via bits RS2–RS0 (registers 0x0E–0x0F), supporting 32.768 kHz, 1 kHz, 64 Hz, or 1 Hz-configurable dynamically via I²C without reset.