Maintaining Time Through the Dark: A Look at the Microchip MCP79400T-I/SN Real-Time Clock

In the world of embedded electronics, maintaining accurate time is a critical function for a vast array of applications, from data logging and medical devices to smart appliances and automation controllers. The Microchip MCP79400T-I/SN stands out as a highly integrated and robust solution designed to provide reliable timekeeping, even when main system power fails.

This versatile IC combines a high-accuracy Real-Time Clock/Calendar (RTCC) with 64 bytes of battery-backed user SRAM and a sophisticated automatic battery switchover circuit. The heart of the device is its real-time clock, which counts seconds, minutes, hours, day, date, month, and year, with automatic leap year compensation valid up to the year 2099. Its low power consumption is essential for extended operation on a backup battery, ensuring time is never lost during a power outage.

A key feature of the MCP79400T-I/SN is its seamless switchover to battery backup. When system VDD is removed, the device automatically and transparently switches to a backup supply, typically a coin cell battery or supercapacitor, without any interruption in timekeeping. The 64 bytes of battery-backed SRAM provide a safe place to store critical system variables or data that must be preserved during a power loss event, enhancing system robustness.

The device also includes two programmable alarms that can generate an interrupt for the microcontroller, a unique, factory-programmed 64-bit serial number for identification, and a power-fail time-stamp feature that records the moment power was lost and restored. Communication is handled via a simple and common I²C serial interface, making it easy to interface with virtually any modern microcontroller.

ICGOOODFIND: The Microchip MCP79400T-I/SN is an exceptional choice for designers seeking a comprehensive, all-in-one timekeeping and memory solution. Its integration of a highly accurate RTCC, non-volatile SRAM, and robust power management logic into a single 8-pin package simplifies design, reduces board space, and significantly improves system reliability for power-sensitive applications.

Keywords: Real-Time Clock (RTC), Battery Backup, SRAM, I²C Interface, Low Power Consumption.