MCP7940NT-I/MS

Real Time Clock Overview

The MCP7940NT-I/MS is a battery-backed I2C Real-Time Clock/Calendar (RTCC) with 64-byte SRAM, manufactured by Microchip Technology. It operates within a voltage range of 1.8V to 5.5V and supports an I2C clock rate up to 400 kHz. The device maintains timekeeping current at 1.2 µA at 3.3V and backup current at 925 nA at 3.0V. It features dual programmable alarms, on-chip digital trimming with ±1 PPM resolution, and automatic switchover to battery backup. The component is housed in an 8-lead MSOP package and functions within an industrial temperature range of -40°C to +85°C.

Real Time Clock Feature Summary

• Real-Time Clock/Calendar with leap year compensation through 2399
• 64-byte battery-backed SRAM for user data storage
• On-chip digital trimming/calibration with ±129 PPM range
• Dual programmable alarms with versatile multifunction output pin

Real Time Clock Applications

• Industrial systems requiring accurate timekeeping
• Battery-powered devices needing low standby current
• Data logging applications utilizing the integrated SRAM
• Systems requiring power-fail timestamping capabilities

Real Time Clock Procurement Notes

Verify that the ordering suffix 'T' corresponds to tape-and-reel packaging as indicated by distributor listings. Confirm the 'I' suffix denotes the Industrial temperature grade (-40°C to +85°C). Ensure compatibility with the 8-lead MSOP footprint during procurement planning.

Real Time Clock Selection Notes

Select this model for applications requiring a compact MSOP package and I2C interface. Ensure the design accommodates external load capacitors for the 32.768 kHz crystal, optimized for 6-9 pF loads. Verify that the system voltage remains within the 1.8V to 5.5V operating range to maintain specified performance characteristics.

Real Time Clock Part Context

This component belongs to the MCP7940N family of RTCCs. Variants such as MCP7940N-I/ST and MCP7940M-I/ST offer similar functionality but differ in package type, such as TSSOP or SOIC. The MCP7940NT-I/MS specifically utilizes the MSOP form factor, distinguishing it from other packages in the series while maintaining identical electrical specifications.

Real Time Clock Replacement Considerations

Direct replacements include other MCP7940N variants like MCP7940N-I/ST or MCP7940N-I/SOIC if package adaptation is feasible. Cross-model substitutes within the MCP794 series may require verification of register compatibility and pinout alignment.