Microchip MCP7940MT-I/MNY: A Comprehensive Real-Time Clock/Calendar Solution with Enhanced Reliability

The Microchip MCP7940MT-I/MNY is a highly integrated Real-Time Clock/Calendar (RTCC) device designed to provide critical timekeeping functions for a wide array of applications, from consumer electronics to industrial systems. This versatile IC combines a precise real-time clock, non-volatile SRAM, and robust power management features into a single, space-saving package, making it an essential component for designs requiring accurate and reliable time tracking.

At the core of the MCP7940MT-I/MNY is a low-power, high-accuracy real-time clock/calendar that maintains seconds, minutes, hours, day, date, month, and year information, with automatic correction for leap years up to 2099. The device operates on a industry-standard I²C serial interface, ensuring easy communication with most microcontrollers and simplifying system integration. A key feature that sets this RTCC apart is its integrated 64-byte battery-backed SRAM. This memory remains powered and retains its data even during a main power failure, providing essential storage for system parameters, event logs, or critical data that must be preserved.

Perhaps the most critical feature for real-world applications is its automatic battery switchover circuitry. The device seamlessly switches to a backup battery supply—such as a coin cell battery or supercapacitor—when the main system power is interrupted. This ensures that the real-time clock continues to run without interruption, and the SRAM contents are protected, guaranteeing data integrity and maintaining accurate timekeeping through power cycles. The MCP7940MT-I/MNY also includes two programmable alarms that can generate interrupts for the host microcontroller, enabling event scheduling or wake-up functions from low-power sleep modes, which is invaluable for power-sensitive designs.

Additional features enhance its utility and robustness. These include a unique, factory-programmed 64-bit serial number for identification, a digital trimming capability to improve oscillator accuracy, and a power-fail time-stamp that records the moment of main power loss. The device is offered in a compact 8-pin TDFN package, making it suitable for space-constrained PCB designs.

ICGOOODFIND: The Microchip MCP7940MT-I/MNY stands out as a highly reliable and feature-rich real-time clock solution. Its combination of battery-switchover capability, non-volatile SRAM, and alarm functions provides designers with a single-component answer for robust timekeeping and data retention, significantly improving system reliability and reducing design complexity.

Keywords: Real-Time Clock (RTC), Battery Switchover, I²C Interface, Non-Volatile SRAM, Power-Fail Protection.