M41ST95WMX6TR

Real Time Clock Overview

The M41ST95WMX6TR is an obsolete serial real-time clock (RTC) IC manufactured by STMicroelectronics. It integrates a clock/calendar, 44 bytes of non-volatile RAM (NVRAM), and microprocessor supervisor functions within a 28-lead SOIC package featuring an embedded crystal. The device operates on a 3.0V supply range (2.7V to 3.6V) with a maximum timing current of 1.4mA at 2.7V. It utilizes a Serial Peripheral Interface (SPI) for communication and supports industrial temperatures from -40°C to 85°C. Key electrical parameters include a battery supply voltage range of 2.5V to 3.5V and an ultra-low battery backup current.

Real Time Clock Feature Summary

• Integrated SPI interface with 44 bytes of general-purpose NVRAM and RTC registers in BCD format.
• Built-in microprocessor supervisor including programmable watchdog timer and power-on reset.
• Automatic battery switchover with write protection during power failures.
• Embedded 32kHz crystal in the 28-pin SOIC (MX) package.

Real Time Clock Applications

• Industrial control systems requiring precise timekeeping and memory retention.
• Embedded devices needing microprocessor supervision and watchdog functionality.
• Battery-powered equipment utilizing automatic power-fail detection.

Real Time Clock Procurement Notes

This component is officially classified as obsolete and no longer manufactured by STMicroelectronics. Verification of availability should rely on distributor stock lists rather than manufacturer channels. Buyers must confirm the specific package variant and ensure compatibility with existing designs before procurement.

Real Time Clock Selection Notes

Select this part only if the design accommodates obsolete components or requires the specific MX package with an embedded crystal. Verify that the system voltage aligns with the 2.7V to 3.6V operating range. Consider the SPI mode requirements (CPOL/CPHA) and ensure the microcontroller supports the necessary interface timing.

Real Time Clock Part Context

The M41ST95W belongs to the M41ST series of serial RTCs. The 'MX' suffix denotes the 28-pin SOIC package with an embedded crystal, distinguishing it from variants requiring external crystals or SNAPHAT battery tops. This specific model represents the 3.0V version of the family.

Real Time Clock Replacement Considerations

Public data identifies the M41ST85WMX6TR as a similar replacement option. Both parts share the same package type and core functionality, though interface differences may exist between SPI and I2C variants within the broader product line.

Real Time Clock FAQ

What is the function of the MX suffix in the part number?

The MX suffix indicates that the device is housed in a 28-pin SOIC package with an embedded 32kHz crystal, eliminating the need for an external crystal component.

How does the device handle power failures?

The M41ST95WMX6TR automatically switches to battery backup when VCC falls below the switchover voltage and inhibits writes to prevent data corruption during power transitions.

What is the maximum serial clock frequency?

The maximum serial clock input frequency (fSCL) is 2 MHz, allowing for high-speed data transfer over the SPI interface.