MCP7940N-I/P

Real Time Clock Overview

The MCP7940N-I/P is a battery-backed I2C Real-Time Clock/Calendar (RTCC) with SRAM in an 8-lead PDIP package. It tracks time using internal counters for hours, minutes, seconds, day of week, date, month, and year, supporting both 12-hour and 24-hour formats. The device features dual programmable alarms, a multifunction output pin, and on-chip digital trimming with ±1 PPM resolution over a ±129 PPM range. It operates from a primary supply of 1.8V to 5.5V and includes automatic switchover to a backup supply (1.3V to 5.5V). Typical timekeeping current is 1.2 µA at 3.3V VCC and 925 nA at 3.0V VBAT.

Real Time Clock Feature Summary

• Real-Time Clock/Calendar with leap year compensation to 2399
• 64-byte battery-backed SRAM
• Dual programmable alarms with flexible comparison options
• On-chip digital trimming for frequency calibration

Real Time Clock Applications

• Systems requiring accurate timekeeping with low power consumption
• Data logging applications utilizing the power-fail time-stamp feature
• Battery-operated devices needing automatic backup switchover

Real Time Clock Procurement Notes

Verify that the ordering suffix 'P' corresponds to the 8-lead PDIP package type as specified in the datasheet. Confirm the temperature grade 'I' indicates the Industrial range (-40°C to +85°C). Ensure the specific revision of the datasheet matches the production lot requirements for any critical timing or electrical parameter validations.

Real Time Clock Selection Notes

Select this component when a through-hole PDIP package is required for the MCP7940N family. The device supports I2C communication up to 400 kHz. Consider the external crystal load capacitance requirements (6-9 pF) and the need for pull-up resistors on the SDA and SCL lines during design integration.

Real Time Clock Part Context

The MCP7940N is part of Microchip's low-cost RTCC series designed for versatility and accuracy. It integrates a real-time clock, calendar, and user-accessible SRAM into a single chip. The device is available in multiple packages including MSOP, SOIC, TSSOP, TDFN, and PDIP, catering to various board space and mounting constraints.

Real Time Clock Replacement Considerations

Other variants within the MCP7940N family share identical functionality but differ in package type, such as MCP7940N-I/SOIC or MCP7940N-I/TSSOP. Verify pin compatibility and physical dimensions before substituting different package suffixes.