MCP7940M-I/SN

Real Time Clock Overview

The MCP7940M-I/SN is a low-cost I2C Real-Time Clock/Calendar (RTCC) with 64-byte SRAM, manufactured by Microchip Technology. It operates within an industrial temperature range of -40°C to +85°C and supports a supply voltage from 1.8V to 5.5V. The device maintains time using a 32.768 kHz crystal or external clock input, featuring on-chip digital trimming for ±129 PPM accuracy. It includes dual programmable alarms, a multifunction output pin, and I2C communication up to 400 kHz. The SN suffix indicates an 8-lead SOIC package.

Real Time Clock Feature Summary

• Real-Time Clock/Calendar with leap year compensation through 2399
• On-chip digital trimming with ±1 PPM resolution
• Dual programmable alarms with flexible comparison options
• 64-byte user-accessible SRAM

Real Time Clock Applications

• Timekeeping in embedded systems requiring I2C interface
• Data logging applications utilizing onboard SRAM
• Alarm-triggered system wake-up or interrupt generation

Real Time Clock Procurement Notes

Verify the ordering suffix 'SN' corresponds to the 8-lead SOIC package variant. Confirm the 'I' suffix matches the required industrial temperature range (-40°C to +85°C). Ensure compatibility with the target I2C bus voltage levels and pull-up resistor requirements for reliable data transfer.

Real Time Clock Selection Notes

Select this component when a cost-effective RTCC with integrated memory is needed. The MCP7940M-I/SN is suitable for designs requiring precise timekeeping without external backup battery switching logic. Consider the SOIC package constraints if board space allows for larger footprints compared to TDFN or MSOP alternatives.

Real Time Clock Part Context

The MCP7940M series includes variants with different packages such as TSSOP, MSOP, PDIP, and TDFN. The MCP7940M-I/SN specifically denotes the Industrial temperature grade housed in an 8-lead Small Outline Integrated Circuit (SOIC) package. Other suffixes like 'ST' or 'MS' indicate different physical form factors within the same functional family.

Real Time Clock Replacement Considerations

Direct replacements include other MCP7940M variants with different packages (e.g., MCP7940M-I/ST for TSSOP) if pinout compatibility is maintained. For PCB redesigns requiring smaller footprints, MCP7940MT-I/MNY (TDFN) may be considered, though layout changes are necessary.