STMicroelectronics M41T00SC64MY6F

Overview

M41T00SC64MY6F from STMicroelectronics is a monolithic integrated circuit combining a serial real-time clock (RTC) with embedded 32.768 kHz crystal and a 64 Kbit (8192 × 8) I²C EEPROM in a single 18-pin SOIC package. It provides BCD-formatted timekeeping (seconds to century), automatic leap-year compensation, battery-backed operation with 600 nA typical V_BAT current, and supports 400 kHz I²C protocol for both RTC and EEPROM functions.

For engineers reviewing the M41T00SC64MY6F datasheet, M41T00SC64MY6F pinout, M41T00SC64MY6F application, or M41T00SC64MY6F equivalent, this device serves as a space- and power-constrained solution for time-stamped data logging, firmware configuration storage, and battery-backed system state retention in industrial controllers, medical instruments, and network infrastructure equipment.

Technical Context

The M41T00SC64 integrates two independent I²C slave devices on one die: the M41T00S RTC (device address 0xD0/0xD1) and the M24C64 EEPROM (device address 0xA0–0xA7). Both share SDA/SCL but operate with distinct control logic, register maps, and timing - RTC uses dedicated calendar registers (0x00–0x07), while EEPROM uses standard byte/page addressing across 8192 bytes.

Its embedded crystal package enables factory calibration to ±5 ppm at 25°C, with aging drift specified as ±3 ppm (Year 1) and ±1 ppm/year thereafter. The integrated power-fail detection circuit automatically switches to V_BAT (2.5–3.5 V) when V_CC drops below threshold, sustaining RTC operation and preserving EEPROM contents without external supervision.

Key Specifications

Pinout & Package

Package: 18-pin SOIC (SOX18), 300-mil width, with embedded 32.768 kHz crystal. RoHS-compliant, ECOPACK® lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS1340Z+ and MCP79411-I/SN, the M41T00SC64MY6F uniquely delivers embedded crystal, 64 Kb EEPROM, hardware write-protect, and factory-trimmed ±5 ppm accuracy in one SOIC package - enabling faster time-to-market for high-reliability, long-life industrial designs.

Availability

M41T00SC64MY6F is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostic devices, network routers, and smart energy meters requiring stable component supply across extended product lifecycles.

Supply support for M41T00SC64MY6F 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 M41T00SC64 belongs to ST's Serial RTC + Memory family, engineered specifically to consolidate timekeeping and nonvolatile storage in resource-constrained embedded systems - reducing PCB area, bill-of-materials, and firmware complexity.

FAQ

What is the function of the WC pin, and how does it interact with I²C write commands?

The WC (Write Control) pin is a hardware-level EEPROM write-enable input. When pulled high, it disables all EEPROM write operations-including byte, page, and write-enable latch commands-regardless of I²C address or data content. This provides fail-safe protection against accidental or malicious writes during system initialization or fault conditions. It operates independently of the I²C bus state and requires no software configuration.

Can the FT/OUT pin output frequencies other than 1 Hz, and how is it configured?

Yes - the FT/OUT pin can be configured via the RTC's control register (address 0x0E, bit 6) to output either 1 Hz, 32.768 kHz, or a user-defined logic signal. When set to frequency mode, it drives an open-drain output synchronized to the internal oscillator; no external components are needed. The 1 Hz option is commonly used for LED blink timing or MCU wake-up interrupts, while 32.768 kHz supports external clock distribution.

How does the embedded crystal affect reflow soldering, and what profile must be followed?

The SOX18 package embeds a fragile 32.768 kHz crystal directly adjacent to the die. ST specifies strict reflow limits: peak temperature must not exceed 240°C for ≤150 seconds total thermal budget, with no infrared (IR) preheat or direct IR exposure. Exceeding these limits risks crystal fracture or frequency shift. Reflow profiles must follow JEDEC J-STD-020D for lead-free packages and avoid thermal shock between zones.

Is the M41T00SC64MY6F still in active production, and what is its obsolescence status?

The M41T00SC64MY6F is marked "Obsolete Product(s)" in ST's official documentation (Rev 3, Jan 2007), indicating end-of-life status. However, Aetrix Electronics maintains legacy inventory with full traceability and offers lifecycle coordination support-including last-time buy planning, cross-reference guidance, and migration path evaluation-to ensure continuity for existing designs still in production or maintenance.