M41ST85WMH6E

Real Time Clock Overview

The M41ST85WMH6E is a serial real-time clock (RTC) and NVRAM supervisor manufactured by STMicroelectronics. It integrates a 400 kHz I²C interface, automatic battery switchover, and write protection for external low-power SRAM. The device operates within a supply voltage range of 2.7 V to 3.6 V and supports an industrial temperature range from -40 °C to +85 °C. It features a 64-byte memory space comprising 44 bytes of NVRAM and 20 memory-mapped RTC registers in BCD format. Key functions include programmable alarms, watchdog timers, and power-on reset capabilities.

Real Time Clock Feature Summary

• Combines serial RTC with microprocessor and NVRAM supervision
• Automatic backup battery switchover and chip-enable gate for write protection
• 400 kHz I²C serial interface with binary coded decimal (BCD) registers
• Programmable watchdog timer and early power-fail warning circuit

Real Time Clock Applications

• Systems requiring non-volatile timekeeping and data retention
• Microprocessor systems needing power-fail detection and reset generation
• Industrial control units operating in harsh environments

Real Time Clock Procurement Notes

Verify the specific suffix MH6E against official STMicroelectronics documentation to confirm package type and tape/reel specifications. Ensure compatibility with the 2.7 V to 3.6 V operating voltage range for the target system design. Cross-reference the SOH-28 package dimensions for PCB layout requirements.

Real Time Clock Selection Notes

Select this component when a combined RTC and supervisor solution is required for 3.0/3.3 V systems. The M41ST85W series is suitable for applications needing automatic switchover to backup batteries without external logic. Consider the 44-byte NVRAM capacity for small data storage needs alongside timekeeping functions.

Real Time Clock Part Context

The M41ST85WMH6E belongs to the M41ST85W family of combination RTC and supervisor ICs. This series is designed for low-power CMOS SRAM processes, offering integrated solutions for timekeeping, memory protection, and system monitoring in a single compact package.

Real Time Clock Replacement Considerations

The M41ST85YMH6E is a related variant within the same family, differing primarily in operating voltage ranges and power-fail deselect voltages. Verify electrical compatibility before substitution.