MCP79412-I/ST

Real Time Clock Overview

The MCP79412-I/ST is a battery-backed I2C Real-Time Clock/Calendar (RTCC) from Microchip Technology, housed in an 8-lead TSSOP package. It operates within a voltage range of 1.8V to 5.5V and supports an industrial temperature range of -40°C to +85°C. The device features a low-power oscillator optimized for 32.768 kHz crystals with on-chip digital trimming. Key specifications include a typical timekeeping current of 1.2 µA at 3.3V and backup current of 925 nA at 3.0V. Memory resources consist of 64 bytes of SRAM, 1 Kbit of EEPROM, and 64 bits of protected EEPROM preprogrammed with an EUI-64 MAC address.

Real Time Clock Feature Summary

• Integrated RTCC with dual programmable alarms and power-fail timestamp logging
• On-chip digital trimming with ±1 ppm resolution for frequency calibration
• 1 Kbit EEPROM with software write-protect and 64-bit protected EUI-64 area
• Versatile multifunction pin (MFP) configurable as alarm output, square wave, or general purpose output

Real Time Clock Applications

• Industrial systems requiring precise timekeeping and data retention during power loss
• Embedded devices needing unique hardware identification via preprogrammed EUI-64 addresses
• Battery-powered IoT nodes utilizing low standby current modes

Real Time Clock Procurement Notes

Verify the specific suffix 'I/ST' corresponds to the Industrial temperature grade (-40°C to +85°C) and TSSOP packaging. Confirm that the EUI-64 MAC address is required, as this distinguishes the MCP79412 from the MCP79410 (unprogrammed) and MCP79411 (EUI-48). Ensure supply voltages align with the 1.8V to 5.5V operating range specified in the datasheet.

Real Time Clock Selection Notes

Select the MCP79412 when a unique 64-bit identifier is necessary for network addressing or security. Compare against MCP79410 if custom programming of the protected EEPROM is preferred over a factory-assigned ID. Ensure external load capacitors are selected to match the crystal's specified load capacitance (6-9 pF) for accurate timing performance.

Real Time Clock Part Context

This component belongs to the MCP7941X family of battery-backed RTCCs. The MCP79412 is functionally identical to the MCP79410 and MCP79411 regarding timekeeping and memory interfaces, differing primarily in the content of the protected EEPROM section. The 'I' denotes the industrial temperature range, while 'ST' indicates the 8-lead TSSOP package type.

Real Time Clock Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided source material.