MCHPMCP7940N

Overview

The MCP7940N is a low-power Real-Time Clock and Calendar (RTCC) from Microchip Technology that utilizes an I2C interface. It features digital timing compensation for crystal calibration, battery backup support to maintain time during power loss, and a dedicated 64-byte SRAM for user data storage. The device is designed to provide accurate timekeeping with minimal power consumption, operating down to 1.8V.

Why Choose This Part

The MCP7940N stands out due to its digital trimming circuit, which allows for software-based calibration of the 32.768 kHz crystal to improve accuracy. It includes a sophisticated power-sense circuit that automatically switches to the backup supply and records the timestamp of the power transition. Additionally, its high ESD protection of over 4,000V makes it robust for industrial environments.

Applications

Getting Started

To evaluate the MCP7940N, you can use the MCP79410 RTCC PICtail Plus Daughter Board or connect a standard SOIC-8 breakout to any I2C-enabled microcontroller. Implementation requires an external 32.768 kHz tuning fork crystal and a backup battery (such as a CR2032) connected to the Vbat pin. Developers should use the I2C bus at speeds up to 400 kHz and consult Microchip Application Note AN2340 for detailed calibration procedures.

MCP7940 Family

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