MCP79522-I/MS

Real Time Clock Overview

The MCP79522-I/MS is a battery-backed SPI Real-Time Clock/Calendar (RTCC) from Microchip Technology, housed in a 10-lead MSOP package. It operates within a voltage range of 1.8V to 3.6V and supports an industrial temperature range of -40°C to +85°C. The device features 64 bytes of SRAM, 2 Kbits of EEPROM, and a 128-bit protected area preprogrammed with an EUI-64 MAC address. Timekeeping includes hundredths of seconds, alarms, and power-fail timestamps, utilizing a 32.768 kHz crystal or external clock input.

Real Time Clock Feature Summary

• Integrated RTCC with 64-byte SRAM, 2 Kbit EEPROM, and EUI-64 unique ID storage
• SPI interface supporting clock rates up to 5 MHz
• Dual programmable alarms and selectable square wave output via MFP pin
• Automatic power switchover with timestamp logging for primary and backup supplies

Real Time Clock Applications

• Embedded systems requiring precise timekeeping and data retention during power loss
• Devices needing secure storage for unique identifiers such as MAC addresses
• Industrial equipment operating within the specified temperature and voltage ranges

Real Time Clock Procurement Notes

Verify that the specific ordering suffix corresponds to the MSOP package type. Confirm the industrial grade (-I) matches the required ambient temperature range of -40°C to +85°C. Ensure the EUI-64 memory configuration aligns with system identification requirements before finalizing procurement.

Real Time Clock Selection Notes

Select this component when an SPI interface is preferred over I2C for RTCC functionality. The MCP79522 variant is appropriate for designs requiring 2 Kbits of non-volatile memory and a pre-burned EUI-64 address. Consider the 10-lead MSOP footprint constraints and ensure adequate decoupling capacitors are placed near VCC and VBAT pins.

Real Time Clock Part Context

This part belongs to the MCP795XX family of battery-backed RTCCs. It shares functional similarities with the MCP7951X series but provides double the EEPROM capacity (2 Kbits vs. 1 Kbit). The 'I' designation indicates industrial temperature rating, while '/MS' specifies the 10-lead MSOP package.

Real Time Clock Replacement Considerations

The MCP79520T-I/MS serves as a functional substitute if the EUI-64 memory is not required. The MCP79512-I/MS offers equivalent memory size but contains an EUI-64 ID instead of blank EEPROM. Verify pin compatibility and software register mapping when substituting.