MCP79412-I/SN

Real Time Clock Overview

The MCP79412-I/SN is a battery-backed I2C Real-Time Clock/Calendar (RTCC) IC manufactured by Microchip Technology in an 8-lead SOIC package. It operates within a supply voltage range of 1.8V to 5.5V and supports industrial temperatures from -40°C to +85°C. The device maintains time using a 32.768 kHz crystal or external clock, featuring on-chip digital trimming for ±129 ppm accuracy. 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 EUI-64™ memory.

Real Time Clock Feature Summary

• Integrated 64-bit Protected EEPROM preprogrammed with a unique EUI-64™ MAC address.
• Dual programmable alarms with flexible comparison options and oscillator failure status flag.
• Automatic power-fail timestamping logs time during switchover to and from battery backup.
• Versatile multifunction pin (MFP) configurable as alarm output, square wave generator, or general purpose output.

Real Time Clock Applications

• Data logging systems requiring precise timestamps for power loss events.
• Embedded devices needing non-volatile storage for unique hardware identifiers.
• Battery-powered equipment utilizing low-power real-time clock functionality.
• Industrial control systems operating within the specified industrial temperature range.

Real Time Clock Procurement Notes

Verify that the specific order suffix corresponds to the SOIC package type. Confirm the 'I' suffix indicates the industrial temperature grade (-40°C to +85°C). Ensure the part number includes the '12' designation to guarantee the inclusion of the preprogrammed EUI-64™ protected memory area, distinguishing it from the MCP79410 or MCP79411 variants.

Real Time Clock Selection Notes

Select this component when a unique EUI-64™ identifier is required alongside standard RTCC functions. The 8-pin SOIC package is suitable for through-hole or surface-mount applications where space allows. Designers must account for the 1.8V minimum operating voltage if interfacing with low-voltage logic. External load capacitors matching the crystal's specified load capacitance (6-9 pF) are mandatory for accurate timing.

Real Time Clock Part Context

This part belongs to the MCP7941X family of battery-backed I2C RTCCs. While functionally similar to the MCP79410 and MCP79411, the MCP79412 is distinguished by its factory-programmed 64-bit EUI-64™ protected EEPROM area. All three variants share identical timekeeping features, memory maps for SRAM and user EEPROM, and interface protocols.

Real Time Clock Replacement Considerations

The ISL12008IB8Z is documented as a similar replacement option. Verify compatibility regarding package dimensions, I2C addressing, and register mapping before substitution. Other family members like the MCP79411 offer EUI-48™ addresses but lack the 64-bit protected area.