MCP79401T-I/SN

Real Time Clock Overview

The MCP79401T-I/SN is a battery-backed I2C Real-Time Clock/Calendar (RTCC) manufactured by Microchip Technology in an 8-lead SOIC package. It tracks time using internal counters for hours, minutes, seconds, day of week, date, month, and year, with leap year compensation through 2399. The device operates on a supply voltage of 1.8V to 5.5V and draws a typical timekeeping current of 1.2 µA at 3.3V. It includes 64 bytes of battery-backed SRAM and protected EEPROM preprogrammed with an EUI-48 MAC address. Key features include dual programmable alarms, digital trimming for oscillator calibration, and automatic switchover to backup power.

Real Time Clock Feature Summary

• I2C compatible serial interface supporting clock rates up to 400 kHz
• 64-byte battery-backed SRAM and 8-byte protected EEPROM with EUI-48 address
• Dual programmable alarms with flexible comparison options
• On-chip digital trimming with ±1 ppm resolution for frequency accuracy

Real Time Clock Applications

• Systems requiring precise timekeeping with low power consumption
• Devices needing unique hardware identification via preprogrammed EUI-48 addresses
• Applications utilizing alarm interrupts or square wave outputs for system control

Real Time Clock Procurement Notes

Verify the specific suffix 'SN' corresponds to the 8-lead SOIC package when sourcing components. Confirm that the industrial temperature range (-40°C to +85°C) meets the operational requirements of the target environment. Ensure the I2C bus pull-up resistors are selected appropriately for the operating voltage and desired clock speed.

Real Time Clock Selection Notes

Select this component over the MCP79400 if a unique EUI-48 MAC address is required for network identification. Choose the MCP79402 if an EUI-64 address is needed instead. Consider the TDFN package option if a smaller footprint is necessary, though the electrical characteristics remain identical across packages.

Real Time Clock Part Context

This part belongs to the MCP7940X family of RTCCs, which also includes the MCP79400 and MCP79402. The primary distinction between these variants lies in the content of the protected EEPROM area: unprogrammed for the MCP79400, EUI-48 for the MCP79401, and EUI-64 for the MCP79402. All variants share the same pinout and core functionality.

Real Time Clock Replacement Considerations

The MCP79400T-I/SN and MCP79402T-I/SN are direct pin-compatible replacements within the same family. Substitution requires verifying that the EEPROM content (EUI-48 vs. none vs. EUI-64) aligns with application needs.